Gen. Comp. Endocrinol. [JOURNAL]
Sun
200 papers
Time the Avenger: Unpredictable environmental disruptions induce changes in neural expression of glucocorticoid receptors in the vocal learning circuit of the male budgerigar.
Moehn KM, Villalba A, Abraham AC … +3 more , Ulmer K, Jawor JM, Wright TF
Gen Comp Endocrinol · 2026 Feb · PMID 41662973 · Full text
Chronic stress can impair behaviors critical for survival, including cognitive traits such as vocal learning. Budgerigars (Melopsittacus undulatus), a parrot species capable of lifelong vocal plasticity, offer a valuable...
Chronic stress can impair behaviors critical for survival, including cognitive traits such as vocal learning. Budgerigars (Melopsittacus undulatus), a parrot species capable of lifelong vocal plasticity, offer a valuable model for studying how stress affects vocal learning circuitry. Previous research has shown that chronic stress induced by unpredictable environmental disturbances reduces vocal plasticity in captive budgerigars, but the molecular mechanisms underlying this change remain unclear. To investigate physiological and molecular responses to these disturbances, we collected data across weekly timepoints in budgerigars subjected to a protocol of mild, unpredictable disturbances. We measured both baseline and stress-induced circulating corticosterone levels and used qPCR to assess expression of glucocorticoid receptor (GR) and mineralocorticoid receptor (MR) mRNA in three brain regions: the magnocellular nucleus of the medial striatum (MMSt), a vocal learning nucleus; the ventral striatum pallidum (VSP), a neighboring striatal region; and the hippocampus, which is involved in stress regulation. Contrary to expectations, there was no statistically significant difference in circulating corticosterone between control and experimental treatments nor among weeks. However, the presence of unpredictable disturbances was associated with significantly reduced GR expression in the MMSt, a region critical for maintaining the stereotypy of learned vocalizations. MR expression in all regions did not differ with treatment or week of sampling. These findings suggest that local downregulation of GR in vocal learning circuitry, rather than systemic hormonal changes, may mediate stress-induced alterations in vocal behavior. This study provides new insight into the neuroendocrine mechanisms by which exposure to unpredictable disturbances affects cognitive function in vocal learners.
Multiplex in situ hybridization chain reaction reveals the spatial organization of six pituitary hormone mRNAs in the Japanese eel.
Watanabe T, Wong MK, Miyahara A … +3 more , Yoshida S, Tsuneoka Y, Tsukada T
Gen Comp Endocrinol · 2026 Feb · PMID 41638583 · Publisher ↗
The anterior pituitary gland regulates growth, development, metabolism, reproduction, and stress responses. In this study, we established a two-round multiplex in situ hybridization chain reaction (isHCR) procedure combi...
The anterior pituitary gland regulates growth, development, metabolism, reproduction, and stress responses. In this study, we established a two-round multiplex in situ hybridization chain reaction (isHCR) procedure combined with a fluorescence-quenching device to visualize the spatial distribution of six pituitary hormone mRNAs (gh, lhb, fshb, tshb, prl, and pomc) in cultured immature Japanese eels. In pituitary sections, prl and tshb were localized to the rostral pars distalis (RPD), whereas lhb, fshb, and gh were distributed in the proximal pars distalis. Pomc was detected in both the RPD and pars neurointermedia, corresponding to adrenocorticotropic hormone- and α-melanocyte-stimulating hormone-producing cells, respectively. Owing to efficient tissue penetration of probes and hairpin DNAs, the isHCR protocol was also applicable to whole-mount pituitary preparations, enabling comprehensive three-dimensional visualization of all six hormone mRNAs. Spatial analyses revealed an orderly organization of hormone-producing cells and demonstrated co-expression of lhb and fshb within the same cells, indicating the presence of bihormonal gonadotrophs in teleosts, with regional variation in their expression. To assess quantitative capability, prl signal intensity-given its established role as a freshwater- (FW) adaptation hormone-was compared between FW- and seawater-(SW) acclimated eels. Prl signals were significantly reduced in SW-acclimated eels, consistent with RT-qPCR results, indicating that isHCR can provide semi-quantitative gene expression information. Furthermore, this method enabled subcellular localization of transcripts, including nuclear heteronuclear RNA of lhb containing intronic sequences. This multiplex spatial transcriptomic approach provides a powerful tool for pituitary research and is broadly applicable to non-model organisms in comparative endocrinology.
Corrigendum to "Roles of estrogens in fish sexual plasticity and sex differentiation" [Gen. Comp. Endocrinol. 277 (2019) 9-16].
Li M, Sun L, Wang D
Gen Comp Endocrinol · 2026 Feb · PMID 41582023 · Publisher ↗
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Endocrine-metabolic effects of kisspeptin in mammals.
Pastor FM, Santos BR, Silva JF … +2 more , Ocarino NM, Serakides R
Gen Comp Endocrinol · 2026 Feb · PMID 41581529 · Publisher ↗
Kisspeptins (Kp) play crucial roles in regulating reproductive functions. In recent decades, new effects of Kp on other systems, such as the cardiovascular, respiratory, and musculoskeletal systems, and its possible ther...
Kisspeptins (Kp) play crucial roles in regulating reproductive functions. In recent decades, new effects of Kp on other systems, such as the cardiovascular, respiratory, and musculoskeletal systems, and its possible therapeutic effects on gestational hypothyroidism, diabetes mellitus, and neoplasms have been identified. Additionally, Kp signaling has been investigated in endocrine-metabolic regulation; nonetheless, there are few reviews on this subject. This study aims to provide a comprehensive overview of the effects of Kp on endocrine-metabolic physiology in mammals. Kp modulates the release of hormones from various endocrine organs, including the hypothalamus, pituitary, gonadal, adrenal, and pancreatic glands. The metabolic effects of Kp exhibit significant sexual dimorphism, manifesting as an increase in metabolic activity, a decrease in body weight in females, and an increase in weight gain in males. Further research is necessary to investigate the effects of Kp on a wide variety of systems, which will help in advancing knowledge in this field. Further sex-specific studies are needed to investigate the therapeutic potential of Kp.
Tachykinin-directed gonadotropin-independent follicular growth: Evolutionary conservation and divergence between mouse and Ciona robusta.
Kawada T, Satake H
Gen Comp Endocrinol · 2026 Feb · PMID 41580210 · Publisher ↗
Follicular development proceeds through gonadotropin-independent and gonadotropin-dependent phases in vertebrates, yet the molecular mechanisms underlying the gonadotropin-independent stage remain poorly understood. Rece...
Follicular development proceeds through gonadotropin-independent and gonadotropin-dependent phases in vertebrates, yet the molecular mechanisms underlying the gonadotropin-independent stage remain poorly understood. Recent studies have revealed that tachykinins (TKs), a conserved family of neuropeptides, directly regulate early-stage (gonadotropin-independent) follicular growth in both the ascidian Ciona robusta and mouse Mus musculus. In ascidians, Ciona TK, CiTK, specifically promotes vitellogenic follicle growth via its receptor (CiTKR) expressed in test cells, upregulating cathepsin D and other proteases. In mice, three TKs (Substance P (SP); Neurokinin A (NKA); and Neurokinin B (NKB)) and their receptors are co-expressed in granulosa cells of secondary follicles, where these TKs act in autocrine/paracrine manners to induce follicle development and oocyte growth. This process involves direct activation of cathepsin D and the JAK1-STAT3-COX-2-prostaglandin pathway. These studies verify that the TK-cathepsin D pathway is an evolutionarily conserved gonadotropin-independent system across Olfactores (ascidians and vertebrates), since the hypothalamus-pituitary-gonadal (HPG) axis is restricted to vertebrates. Notably, the TK-mediated pathway is active prior to sexual maturity in mice, suggesting that normal early-stage follicle development is essential for reproductive capacity and offspring viability. Collectively, investigation of TK-driven gonadotropin-independent folliculogenesis provides new insights into reproductive and evolutionary biology.
Effects of melanocortin receptor agonists and antagonists on exploratory activity: a review.
Lalonde R, Strazielle C
Gen Comp Endocrinol · 2026 Feb · PMID 41558543 · Publisher ↗
In view of recent interest in the regenerative powers of alpha-melanocyte-stimulating hormone (α-MSH), the effects of melanocortin receptor agonists and antagonists were reviewed in open-field, elevated plus-maze, hole-b...
In view of recent interest in the regenerative powers of alpha-melanocyte-stimulating hormone (α-MSH), the effects of melanocortin receptor agonists and antagonists were reviewed in open-field, elevated plus-maze, hole-board, and light-box tests of exploratory activity. In the open-field, low doses of melanocortin receptor agonists increase ambulatory activity and rearing but decrease center zone activity and duration under some conditions. In the elevated plus-maze, MSH receptor agonists generally decrease open arm exploration while MSH receptor antagonists increase open arm exploration, possibly caused by effects in amygdala, medial preoptic area, and ventromedial hypothalamus. Hole-board and light-box test results are preliminary but indicate a similar pattern of an anxiogenic response to melanocortin receptor agonists and an anxiolytic response to antagonists. At low doses, melanocortin receptor agonists are liable to increase general activity, a factor that needs to be taken into account when examining its regenerating action. Melanocortin receptor antagonists decrease anxiety in the elevated plus-maze and thereby may serve a useful function while increasing appetite.
Toxins in disguise: Neuropeptide mimicry across animal venoms.
Koch TL, Safavi-Hemami H
Gen Comp Endocrinol · 2026 Feb · PMID 41554321 · Full text
Neuropeptides and peptide hormones form a highly diverse class of signaling molecules found across the animal kingdom that regulate key physiological processes, including growth, metabolism, reproduction, and behavior. M...
Neuropeptides and peptide hormones form a highly diverse class of signaling molecules found across the animal kingdom that regulate key physiological processes, including growth, metabolism, reproduction, and behavior. Many venomous animals have evolved "doppelgänger toxins" that mimic these endogenous peptides, allowing them to manipulate the physiology of their prey or predators. These toxins typically act on the same receptors as the peptides they mimic, most commonly G protein-coupled receptors, but also receptor tyrosine kinases, membrane-bound guanylyl cyclases, and ion channels. Although doppelgänger peptides have been described in other ecological contexts, this review focuses on venom-derived mimics, summarizing their molecular characteristics, evolutionary context, and biological functions. We catalogue examples spanning conserved bilaterian neuropeptides to lineage-specific families and discuss their translational potential in medicine and pest control.
Role of gonadal soma-derived growth factor (gsdf) on sex-differentiation in Nile tilapia, Oreochromis niloticus.
Arai T, Tanaka S, Sakon M … +2 more , Gao H, Ijiri S
Gen Comp Endocrinol · 2026 Feb · PMID 41534571 · Publisher ↗
Molecular sex differentiation is regulated by complex transcriptional dynamics. In Nile tilapia, ovarian differentiation requires the synthesis of estradiol-17β (E), in which forkhead box L2 (foxl2) and ovarian aromatase...
Molecular sex differentiation is regulated by complex transcriptional dynamics. In Nile tilapia, ovarian differentiation requires the synthesis of estradiol-17β (E), in which forkhead box L2 (foxl2) and ovarian aromatase (cytochrome P450, family 19, subfamily A, polypeptide 1a; cyp19a1a) play critical roles, whereas gonadal soma-derived growth factor (gsdf) and doublesex and mab-3-related transcription factor 1 (dmrt1) are implicated in testicular differentiation. During the early phase of molecular sex differentiation, gsdf mRNA is expressed to a significantly higher degree in the undifferentiated gonads of XY males than in XX females. However, the molecular mechanisms by which gsdf promotes testicular differentiation remain poorly understood. We hypothesized that gsdf acts by suppressing ovarian differentiation or promoting testicular differentiation through the upregulation of dmrt1. To clarify the relationship with dmrt1, we performed fluorescent double in situ hybridization on undifferentiated gonads and testes. Furthermore, recombinant Gsdf (rGsdf) was produced and microinjected into the body cavity of XX larvae to investigate its effects on the expression of sex differentiation-related genes in undifferentiated gonads. We demonstrated that gsdf and dmrt1 were expressed in distinct cell populations in undifferentiated gonads, whereas partial co-localization occurred in certain cells within the testes. Administration of rGsdf led to a significant decrease in the expression of E synthesis-related genes, including foxl2, hydroxysteroid 17-beta dehydrogenase 1 (hsd17b1), and cyp19a1a. These findings suggest that gsdf suppresses E production and that its expression is regulated not only by dmrt1 but also by other factors during the molecular sex differentiation phase in Nile tilapia.
Development of a sandwich ELISA for serum leptin measurement in chub mackerel across reproductive stages and feeding and nutritional statuses.
Ohga H
Gen Comp Endocrinol · 2026 Feb · PMID 41525906 · Publisher ↗
Leptin is an adipocyte-derived hormone that links nutritional status with endocrine and reproductive functions. However, only a limited number of teleost species allow reliable measurement of circulating leptin. In this...
Leptin is an adipocyte-derived hormone that links nutritional status with endocrine and reproductive functions. However, only a limited number of teleost species allow reliable measurement of circulating leptin. In this study, we aimed to develop a specific and sensitive sandwich enzyme-linked immunosorbent assay (ELISA) for measuring serum leptin A in chub mackerel (Scomber japonicus) using two polyclonal antibodies. Validation assays confirmed high specificity, sensitivity, recovery, linearity, and parallelism, demonstrating the effectiveness of the sandwich ELISA in leptin quantification. Using the system, we analyzed leptin dynamics under several physiological conditions. Although no sex-related difference was observed in the circulating leptin levels, leptin concentrations were significantly higher in mature adults than in immature fish, suggesting its role in signaling the attainment of the threshold body weight required for reproduction. Postprandial analysis revealed a transient increase in circulating leptin at 2 h after feeding, which returned to baseline by 4 h, indicating its involvement in short-term appetite regulation. During long-term fasting, circulating leptin showed a non-significant upward trend, suggesting its possible role in metabolic responses under energy depletion. In conclusion, our study established a reliable assay system and, for the first time, characterized circulating leptin dynamics in chub mackerel. The findings could lay the foundation for future studies on nutritional and reproductive physiology of teleost fish.
Expression profiles of the sirtuin genes family during ovarian development and hormonal regulation in Pampus argenteus.
Wang C, Zhang H, Wang Y … +4 more , Zhang K, Wang X, Wang X, Guo C
Gen Comp Endocrinol · 2026 Feb · PMID 41525905 · Publisher ↗
Sirtuins (Sirt) are a class of NAD + -dependent type III histone deacetylases that play significant roles in energy metabolism and reproductive regulation. To explore the role of the sirt genes family in the ovarian deve...
Sirtuins (Sirt) are a class of NAD + -dependent type III histone deacetylases that play significant roles in energy metabolism and reproductive regulation. To explore the role of the sirt genes family in the ovarian development of Pampus argenteus and its significance in artificial breeding, this study conducted a systematic investigation using phylogenetic tree analysis and real-time fluorescence quantitative PCR. Phylogenetic analysis indicated that the sirt gene of the P. argenteus was most closely related to those of Thunnus maccoyii and Thunnus. albacares. Specific expression analysis revealed that the expression levels of sirt1, sirt2, sirt5, sirt6, and sirt7 in the ovary were significantly higher than those in other tissues (P < 0.05). In the analysis of ovarian development during stage I-VI, sirt1, sirt3, and sirt5 reached their peak expression during the pre-maturation stage, while sirt6 had the highest expression in stage VI. The in vitro steroid hormone immature egg culture experiment showed that estradiol significantly inhibited the expression of sirt1, sirt2, sirt4, sirt5, sirt6 genes. Luteinizing hormone inhibited the expression of sirt1, sirt2 and sirt4, but promoted the expression of sirt3 and sirt5. Human chorionic gonadotropin slightly upregulated the expression of sirt1. Intraperitoneal injection of HCG and LH shows differential regulation on the expression of sirt genes in different brain regions, indicating that they were involved in the neuroendocrine regulatory pathway. In conclusion, the sirt genes family, especially sirt1, which showed peak expression during the critical period of early egg growth and before maturation, may promote ovarian maturation by regulating meiotic recovery and energy metabolism pathways. This study provides a theoretical basis for researching the reproductive regulation of P. argenteus and optimizing artificial breeding techniques.
Latent trait-like component identified for bottlenose dolphin fecal glucocorticoid metabolite concentrations.
Lauderdale LK, Granger DA, Walsh MT … +1 more , Miller LJ
Gen Comp Endocrinol · 2026 Feb · PMID 41468925 · Publisher ↗
Cortisol, an end product of hypothalamic-pituitary-adrenal (HPA) axis activation, plays a critical role in responding to arousal and restoring homeostasis. Chronic or repeated activation of the HPA axis may lead to physi...
Cortisol, an end product of hypothalamic-pituitary-adrenal (HPA) axis activation, plays a critical role in responding to arousal and restoring homeostasis. Chronic or repeated activation of the HPA axis may lead to physiological dysregulation that has potential negative health consequences. Quantifying stable, trait-like components of fecal glucocorticoid metabolite concentrations in animals could have a marked effect on investigating physiological stress responses and establishing higher resolution baselines for intra-individual clinical management, yet no studies have examined latent state-trait (LST) models for any non-human animals. Using an LST model, trait and state sources of fecal glucocorticoid metabolite variation were decomposed. Fecal samples were collected from 179 common bottlenose dolphins (Tursiops truncatus) in 41 habitats in late afternoon. The fit indices were excellent suggesting that LST models can be applied to bottlenose dolphin glucocorticoid metabolite measures. Trait factors (i.e., individual specific) accounted for an estimated 49 % of the variance in glucocorticoid metabolite concentrations and state factors (i.e., day-to-day factors) accounted for an estimated 41 % of the variance. This work suggests that LST models provide valuable evidence of a trait-like component in glucocorticoid metabolites in bottlenose dolphins that can be widely used in clinical management and research settings.
Life after precocious male maturation in a semelparous salmonid: A physiological perspective in Chinook salmon, Oncorhynchus tshawytscha.
Larsen DA, Middleton MA, Harstad DL … +2 more , Spangenberg DK, Fuhrman AE
Gen Comp Endocrinol · 2026 Jan · PMID 41412266 · Publisher ↗
Spring Chinook salmon, Oncorhynchus tshawytscha, are typically semelparous, dying after a single lifetime spawning event. However, observations of survival following maturation in males that mature at age-1 (common names...
Spring Chinook salmon, Oncorhynchus tshawytscha, are typically semelparous, dying after a single lifetime spawning event. However, observations of survival following maturation in males that mature at age-1 (common names: precocious parr or microjacks) have been documented, but little is known regarding their post-maturation physiology. In this investigation, mature microjacks were fed either a high or low winter ration to examine potential effects of feeding regime on mortality, smoltification and rematuration the following year. We measured a series of physiological factors including survival, size, percent whole body solid (an index of whole body lipid), and gill Na+/K+-ATPase activity (an index of smoltification). We also analyzed a series of maturation indices including plasma 11-ketotestosterone (11-KT), gonadosomatic index (GSI), pituitary follicle stimulating hormone (fshb) and luteinizing hormone (lhb) beta-subunit mRNA, and testicular histology in male fish following maturation as microjacks. In both treatments, the proportion of males that survived (High Ration: 0.91, Low Ration: 0.87) and rematured (High Ration: 1.0, Low Ration: 1.0) was very high, more indicative of iteroparity than semelparity. The low winter ration may have caused a slight delay in rematuration as evidenced by delayed fshb expression and 11-KT secretion in the spring. However, there was no evidence microjacks smolted in the spring after maturation at age-1. From a fisheries conservation perspective, the potential for iteroparity in microjacks (survival to remature at age-2) means it is possible they contribute genetically more than once when breeding in the natural environment.
Amiodarone disrupts thyroid hormone signaling networks governing early heart development in the chick embryo.
Vaishnav J, Maurya A, Varadarajan V … +1 more , Balakrishnan S
Gen Comp Endocrinol · 2026 Jan · PMID 41401880 · Publisher ↗
Thyroid hormones (THs) are indispensable regulators of vertebrate embryogenesis, orchestrating signaling networks that direct cardiac morphogenesis. To investigate how disruption of this pathway impacts early development...
Thyroid hormones (THs) are indispensable regulators of vertebrate embryogenesis, orchestrating signaling networks that direct cardiac morphogenesis. To investigate how disruption of this pathway impacts early development, fertilized Gallus domesticus eggs were exposed to amiodarone, a potent TH receptor (THR) antagonist and deiodinase inhibitor. Treated embryos displayed pronounced defects, including impaired heart looping, edema, increased apoptotic regions and sustained bradycardia during Hamburger-Hamilton stages 12 to 18. By day 10, histology revealed significant thinning of ventricular and atrial walls, with the compact ventricular layer reduced by ∼22 % while trabeculae were relatively preserved. These changes were accompanied by reduced acetylcholinesterase activity, indicating impaired neurocardiac regulation. Molecular analyses showed broad downregulation of WNT11, GATA4/5, TBX20, HAND2, BMP4, SHH, FGF8, MYOD, and MYOSIN, together with decreased PCNA and compensatory upregulation of GATA6. Interestingly, discrepancies between transcript and protein levels suggested post-transcriptional control under hypothyroid conditions. In silico promoter scanning identified thyroid hormone response elements within HAND2, GATA6, TBX5, PITX2, and BMP4, linking maternal TH signaling directly to lateral plate mesoderm gene networks. Flow cytometry and whole-mount immunolocalization confirmed reduced expression and altered localization of MYOD and MYOSIN, including loss of the normal heart-tube-restricted MYOD signal. Collectively, these findings establish that TH signaling networks coordinate structural, functional, and molecular programs essential for early cardiogenesis. Amiodarone-induced THR blockade recapitulates developmental hypothyroidism, providing mechanistic insight into how maternal TH deficiency or endocrine-disrupting exposures may contribute to congenital heart defects.
Hierarchical regulation of steroid synthesis in ovarian follicles drives progesterone surge in cloudy catshark.
Inoue R, Kawano M, Shimoyama K … +6 more , Saito M, Arimura S, Tokunaga K, Takagi W, Shing Wong MK, Hyodo S
Gen Comp Endocrinol · 2026 Jan · PMID 41397581 · Publisher ↗
We previously demonstrated that two major hormonal phases, testosterone (T)-phase and progesterone (P4)-phase, which are marked by high plasma T and P4, respectively, appeared in each egg-laying cycle of cloudy catshark....
We previously demonstrated that two major hormonal phases, testosterone (T)-phase and progesterone (P4)-phase, which are marked by high plasma T and P4, respectively, appeared in each egg-laying cycle of cloudy catshark. In the present study, the mechanisms underlying the cyclical fluctuations of sex steroids were investigated by follicular steroid measurement and gene expression analyses in vivo and in vitro. In the ovary of catshark, a hierarchical pattern of follicles of increasing sizes is present. Estradiol (E2) was produced by early vitellogenic follicles, while T was produced by mid- to late-vitellogenic follicles. The production of T was downregulated in the follicles at P4-phase, concomitant with the significant decreases in expression of cyp17a1 gene encoding P450c17, an enzyme converting P4 to androgen. Meanwhile, P4 was exclusively produced by preovulatory F1 follicles only at P4-phase, which was related in time to a marked upregulation of steroidogenic acute regulatory protein 2 (star2), suggesting that star2 is a key regulatory factor for inducing the P4 surge. Our newly established in vitro follicle culture system confirmed the secretion of E2, T and P4 from follicles at the different hierarchical stages. These findings provide clear evidence that follicular hierarchy is an important driver of the cyclical secretion of steroid hormones by follicles, and of circulating steroids in plasma, in the cloudy catshark.
IDENTIFICATION of NLP-5 and NLP-6 as potential ligands for the NPR-9 receptor in Caenorhabditis elegans.
Torki F, Bendena WG, Chin-Sang ID
Gen Comp Endocrinol · 2026 Jan · PMID 41360305 · Publisher ↗
Neuropeptides in Caenorhabditis elegans regulate physiological and behavioural responses to environmental cues, influencing locomotion, feeding, and fat storage via interactions with G-protein coupled receptors (GPCRs)....
Neuropeptides in Caenorhabditis elegans regulate physiological and behavioural responses to environmental cues, influencing locomotion, feeding, and fat storage via interactions with G-protein coupled receptors (GPCRs). C. elegans expresses a diverse repertoire of neuropeptides, including FMRFamide-related peptides, neuropeptide-like peptides (NLPs), and insulin-like peptides (INSs). Among these, the galanin/allatostatin-like GPCR, NPR-9, localized in the AIB interneurons, regulates locomotory behaviours (roaming and dwelling) and fat accumulation by inhibiting AIB activity. Recent studies identified NLP-1 as a ligand for NPR-9, modulating behaviour through direct receptor interaction. However, our research explored whether other neuropeptides, specifically NLP-5 and NLP-6 (allatostatin A-type/galanin-like neuropeptides), could also function as NPR-9 ligands, despite evidence suggesting NLP-1 as the primary ligand. In this study, we characterized phenotypes associated with NPR-9 receptor function, including Omega turns, roaming, and fat accumulation. Loss-of-function mutations in nlp-5, nlp-6, and nlp-1 exhibited behavioural phenotypes similar to npr-9 mutants, suggesting that NLP-5 and NLP-6 may act as additional ligands for NPR-9 or affect NPR-9 signalling. Furthermore, double-mutant analyses with candidate ligand genes suppressed phenotypes associated with NPR-9 overexpression, reinforcing the hypothesis that these neuropeptides may regulate NPR-9-mediated signalling.
Potential role of COUP-TF in regulating major yolk protein gene expression in sea urchin.
Higuchi I, Tsue S, Kitano Y … +5 more , Nishimiya O, Hosokawa M, Beppu F, Ura K, Takagi Y
Gen Comp Endocrinol · 2026 Jan · PMID 41360304 · Publisher ↗
Major yolk protein (MYP) serves as a critical nutrient reservoir for gonadal development in sea urchins, but the transcriptional regulation of its encoding gene remains largely uncharacterized. Here, we cloned and analyz...
Major yolk protein (MYP) serves as a critical nutrient reservoir for gonadal development in sea urchins, but the transcriptional regulation of its encoding gene remains largely uncharacterized. Here, we cloned and analyzed the MYP promoter from Mesocentrotus nudus and found two conserved elements with putative binding sites for the orphan nuclear receptor COUP-TF (chicken ovalbumin upstream promoter-transcription factor). We cloned the full-length cDNA encoding COUP-TF from M. nudus (MnCOUP-TF). The cDNA encoded a 472-amino acid protein highly homologous to other COUP-TF/SVP subfamily members. RT-PCR and qPCR analyses revealed that transcripts of both MnCOUP-TF and MYP were present in several tissues, including gonads, and their levels exhibited a significant positive correlation during gonadal maturation (R = 0.6764, p < 0.01). Electrophoretic mobility shift assays demonstrated specific binding of MnCOUP-TF to the MYP promoter, and transactivation assays showed that MnCOUP-TF activates transcription through these sites. Furthermore, total lipids extracted from gonadal tissue enhanced MnCOUP-TF-dependent reporter activity in a dose-dependent manner. This enhancement was comparable to the effect of 9-cis-retinoic acid, a compound known to activate COUP-TF at high concentrations, although it is not considered to be a physiological COUP-TF ligand. These results suggest that MnCOUP-TF regulates MYP expression in a ligand-dependent manner and that endogenous activators may be present in gonadal lipids. To our knowledge, this is the first molecular evidence implicating COUP-TF in yolk protein gene regulation in sea urchins, providing new insights into nuclear receptor-mediated control of reproduction in marine invertebrates.
Characterization and expression of urotensin1 and urotensin2 genes in the caudal neurosecretory system of the small-spotted catshark Scyliorhinus canicula.
Bichon B, Alfama G, Gaillard AL … +3 more , Quan FB, Sourdaine P, Tostivint H
Gen Comp Endocrinol · 2026 Jan · PMID 41314559 · Publisher ↗
The caudal neurosecretory system (CNSS) is a neuroendocrine complex unique to fish. In teleosts, the neuroendocrine neurons of the CNSS, called Dahlgren cells, are located in the terminal part of the spinal cord and proj...
The caudal neurosecretory system (CNSS) is a neuroendocrine complex unique to fish. In teleosts, the neuroendocrine neurons of the CNSS, called Dahlgren cells, are located in the terminal part of the spinal cord and project to a neurohemal organ, the urophysis, from which several hormones are released. The two major hormones secreted by Dahlgren cells are two neuropeptides called urotensin 1 (UI), related to the corticotropin-releasing hormone and urotensin 2 (UII), related to somatostatin. In cartilaginous fishes, the CNSS organization is simpler than in teleosts due to the absence of urophysis. As a consequence, Dahlgren cells project into a diffuse neurohemal region located at the ventral base of the spinal cord. Such an organization of the CNSS is considered as primitive. An important feature of Dahlgren cells in cartilaginous fishes is also their huge size. The goal of the present study was to provide more insight into the CNSS in cartilaginous fish, which has been poorly studied so far. For this purpose, we used the small-spotted catshark Scyliorhinus canicula, as a model. We first cloned the cDNAs encoding for both catshark UI (uts1) and UII (uts2). This search revealed the existence of two copies of the uts1 gene, uts1a and uts1b, that are tandemly arranged. We then determined by RT-qPCR the expression pattern of the uts1a, uts1b, and uts2 genes in various catshark tissues. Our results revealed that uts1a and uts2 genes are primarily expressed in giant cells of the caudal spinal cord, that likely correspond to Dahlgren cells. The uts1a transcript was also detected in the epididymis head of the testis but at a much lower level. In contrast, the uts1b transcript was detected at very low levels in all tissues examined. Further study by double fluorescence in situ hybridization showed that in the caudal spinal cord, all uts1a mRNA-containing cells expressed uts2 while only about half of the uts2-expressing cells also expressed uts1a. Taken together these results suggest the existence of two populations of Dahlgren cells: one of which expressing solely uts2 and the other expressing both uts1a and uts2. In conclusion, our work showed that, as in teleosts, uts1 and uts2 are two potentially useful markers for studying the CNSS in cartilaginous fish.
Assessing stress in a mammal from plasma and feces: A nutritional mismatch between the diet needed and the food -available.
Boonstra R, Castillo J, Karels TJ … +3 more , Dobson FS, Palme R, Bosson CO
Gen Comp Endocrinol · 2026 Jan · PMID 41276192 · Publisher ↗
A lack of agreement between the diet an animal needs for reproduction and survival and the food available in its environment has major impact on its fitness. The complexity of their digestive system is critical and may a...
A lack of agreement between the diet an animal needs for reproduction and survival and the food available in its environment has major impact on its fitness. The complexity of their digestive system is critical and may affect stress axis function. The squirrel family (sciurids) have a very simple gut and do not have the microbiome to digest high fiber foods well. Thus, they forage preferentially on forbs, seeds, and fungi, and avoid hard-to-digest grasses. We compared two measures of their stress axis - plasma free cortisol, a glucocorticoid (GC), and fecal cortisol metabolites (FCMs) - in Columbian ground squirrels (Urocitellus columbianus) from two meadows as they were building up body reserves in July for their pending hibernation. One meadow was natural with an abundance of forbs and the other unnatural with an abundance of grasses that had been seeded as a horse pasture. Our two measures went in the opposite direction: GC levels were lower on the natural meadow but FCMs were higher, whereas GC levels were higher on the grass meadow but FCMs lower. The fecal fiber content was lower on the natural meadow. Thus, when interpreting FCM levels, it is critical to understand both the digestive system of the study mammal and its diet to interpret stress axis function.
In silico analysis of the slipper lobster (Thenus australiensis) neuropeptidome reveals unique enrichment of peptide hormones in reproductive tissues using multi-tissue transcriptomics.
Banks TM, Glendinning S, Lewis C … +4 more , Bhojwani A, Fitzgibbon QP, Smith GG, Ventura T
Gen Comp Endocrinol · 2026 Jan · PMID 41271029 · Publisher ↗
The slipper lobster, Thenus australiensis has gained attention as a candidate species for aquaculture production. Recent studies have investigated various aspects of rearing T. australiensis in an aquaculture setting, ho...
The slipper lobster, Thenus australiensis has gained attention as a candidate species for aquaculture production. Recent studies have investigated various aspects of rearing T. australiensis in an aquaculture setting, however genetic resources are limited. Here, we generated the first multiple tissue transcriptome library for T. australiensis for immature male and female lobster tissues including the eyestalk, brain, testis, ovary, 3rd and 5th walking leg regions, hepatopancreas, stomach and muscle, with a total of 38 samples sequenced. From this transcriptome, we describe the neuropeptidome of T. australiensis and provide neuropeptide precursor expression patterns across tissues. The eyestalk and brain expressed the most neuropeptide precursor genes as expected, although surprisingly several others were enriched in the testis and ovary. Members of the allatostatin, crustacean hyperglycaemic hormone, and insulin like peptide family were among those highly expressed in gonad tissue, alongside peptides previously linked to reproduction such as corazonin and crustacean female sex hormone, and other neuropeptides without any established roles in reproduction. This repertoire of neuropeptides possibly related to reproductive processes provides a basis for future functional characterisation and may offer an avenue for enhancing production with aquaculture biotechnology.
A window into vitamin effects on biomineralization in octocorals.
Forin C, Allemand D, Tambutté S … +1 more , Ganot P
Gen Comp Endocrinol · 2026 Jan · PMID 41232651 · Publisher ↗
Vitamins are essential micronutrients involved in various biochemical processes, such as serving as cofactors, antioxidants, and regulators of calcium metabolism. In vertebrates, vitamins D, K, and C are particularly kno...
Vitamins are essential micronutrients involved in various biochemical processes, such as serving as cofactors, antioxidants, and regulators of calcium metabolism. In vertebrates, vitamins D, K, and C are particularly known for supporting bone health and mineralization. However, the role of vitamins in biomineralization processes in marine invertebrates, such as octocorals (cnidarians) that produce internal skeletal structures called sclerites, remains largely unexplored. This study uses an in vivo injection method in the octocoral Sarcophyton sp. to assess the effects of various vitamins on sclerite formation over 21 days. Calcification was monitored using calcein, a fluorescent marker, and analyzed by confocal microscopy combined with particle analysis. Our results indicate that vitamin D promotes sclerite formation, whereas vitamin C appears to inhibit this process, suggesting distinct roles for specific vitamins in octocoral biomineralization. These findings provide experimental evidence of vitamin-mediated regulation of biomineralization in octocorals. By identifying conserved pathways in cnidarian skeletal formation, this study lays the groundwork for future research in coral physiology, and more broadly on comparative endocrinology, and may contribute to broader insights into coral resilience.
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