General and comparative endocrinology最新文献

{"title":"Diurnal variation of plasma corticosterone, glucose, and protein levels in captive rice field frog Hoplobatrachus rugulosus (Wiegmann, 1834)","authors":"Artit Apibanpathomrat ,&nbsp;Wichase Khonsue ,&nbsp;Khattapan Jantawongsri ,&nbsp;Noppadon Kitana","doi":"10.1016/j.ygcen.2026.114933","DOIUrl":"10.1016/j.ygcen.2026.114933","url":null,"abstract":"<div><div>Corticosterone (CORT) is a major stress hormone in amphibians that shows rhythmic daily variation and plays a central role in metabolic regulation. Those responses can potentially be altered under captive conditions. This study aimed to investigate daily variations in plasma CORT, glucose, and total protein (TP) levels in captive <em>Hoplobatrachus rugulosus</em> during wet and dry seasons. Blood samples were collected every 4 h over a 24-h period from adult male and female frogs and analyzed, revealing sex-specific diurnal and seasonal patterns in these physiological parameters. In males, plasma CORT levels exhibited significant diurnal variation in both seasons, with lower levels at night compared to the afternoon, whereas females showed significant seasonal differences in CORT levels. Glucose levels differed between seasons in males, suggesting seasonal changes in metabolic demand, while females showed diurnal variation during the wet season, likely associated with feeding schedules. The TP levels varied seasonally in males, whereas females displayed diurnal variation during the dry season, indicating sex-specific strategies in energy allocation and physiological regulation under contrasting environmental conditions. These findings highlight seasonal and sex-specific physiological adjustments in captive <em>H. rugulosus</em>, providing insights that could improve frog rearing practices in Thailand.</div></div>","PeriodicalId":12582,"journal":{"name":"General and comparative endocrinology","volume":"380 ","pages":"Article 114933"},"PeriodicalIF":1.7,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147716541","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Hormonal actions of relaxin-like gonad-stimulating peptide in starfish","authors":"Masatoshi Mita","doi":"10.1016/j.ygcen.2026.114930","DOIUrl":"10.1016/j.ygcen.2026.114930","url":null,"abstract":"<div><div>Oocyte maturation is a process that occurs in the ovaries, where immature oocytes resume meiosis to attain competence for normal fertilization after ovulation/spawning. Gonadotropic hormone (GTH) is the initial trigger of this process. Relaxin-like gonad-stimulating peptide (RGP) in starfish is the first neuropeptide hormone with GTH-like activity identified in invertebrates. RGP is a heterodimeric peptide consisting of A- and B-chains, belonging to the insulin superfamily, particularly the relaxin group. This review describes the mechanism of action of RGP from oocyte maturation to ovulation in starfish. Recently, RGP has been found to be distributed in the nerve plexus around gonoducts connecting gonads and gonopores. This suggests that RGP secreted from the gonoducts stimulates ovarian follicle cells and testicular interstitial cells to produce the maturation-inducing hormone, 1-methyladenine (1-MeAde). RGP acts on receptors, G proteins, and adenylyl cyclase in these target cells, increasing intracellular cyclic AMP levels and resulting in 1-MeAde production. The RGP receptor is a rhodopsin-like G protein-coupled receptor which is homologous to human relaxin family peptide receptor and <em>Drosophila</em> leucine-rich repeat G protein-coupled receptor 3. Interestingly, the Gαs protein, which is important for RGP signal transduction, is absent from follicle cells surrounding the small oocytes before the breeding season, but is expressed during the breeding season. Neither RGP nor 1-MeAde is directly involved in the gonadal contraction required for ovulation. While some neuropeptides may be involved in gonadal contraction and relaxation, 1-MeAde likely induces the secretion of non-neuronal acetylcholine in the ovaries and testes, resulting in muscle contraction of the gonadal wall to release mature oocytes and sperm.</div></div>","PeriodicalId":12582,"journal":{"name":"General and comparative endocrinology","volume":"380 ","pages":"Article 114930"},"PeriodicalIF":1.7,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147662338","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Constitutive activation of MC1R in the large-billed crow (Corvus macrorhynchos) and its potential role in black plumage","authors":"Saya Nakano ,&nbsp;Yuichi Tashiro ,&nbsp;Hibiki Fukuchi ,&nbsp;Sayaka Aizawa ,&nbsp;Sakae Takeuchi","doi":"10.1016/j.ygcen.2026.114924","DOIUrl":"10.1016/j.ygcen.2026.114924","url":null,"abstract":"<div><div>Melanin-based plumage coloration in birds is largely regulated by the melanocortin 1 receptor (MC1R), a G protein–coupled receptor that promotes eumelanin synthesis via cAMP signaling. In domestic chickens, constitutively activating mutations such as the MC1R^E (E92K) allele cause melanistic phenotypes, demonstrating that persistent MC1R activation can drive generalized darkening. However, to our knowledge, no experimental study has directly demonstrated constitutive MC1R activation in wild birds exhibiting uniformly black plumage. We investigated the sequence and signaling properties of MC1R from the Large-billed Crow (<em>Corvus macrorhynchos</em>), a species with strongly eumelanin-dominant plumage. Crow MC1R exhibited elevated basal cAMP signaling and minimal responsiveness to α-melanocyte-stimulating hormone (α-MSH) in both stable Chinese hamster ovary (CHO-K1) cells and transient CRE-luciferase assays in HEK293T cells, demonstrating ligand-independent activation comparable to that observed in the melanizing chicken MC1R^E (E92K) allele. Comparative sequence analysis identified multiple substitutions conserved across <em>Corvus</em> species. Among these, E12K and E18K were functionally evaluated based on prior associations with melanism in other birds. Although E12K modestly increased basal signaling in chicken MC1R, E18K alone or in combination with E12K did not reproduce crow-level constitutive activity, and reciprocal substitutions in crow MC1R failed to abolish ligand-independent activation. These findings demonstrate that crow MC1R possesses constitutive activity and suggest that this phenotype reflects lineage-specific modifications rather than a single activating substitution. Our results provide experimental evidence that constitutive MC1R activation is a plausible molecular mechanism that may contribute to the black plumage in the Large-billed Crow, although a direct causal relationship remains to be established.</div></div>","PeriodicalId":12582,"journal":{"name":"General and comparative endocrinology","volume":"380 ","pages":"Article 114924"},"PeriodicalIF":1.7,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147620722","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Functional divergence of NPR1 paralog in the Japanese eel: Identification and neuroanatomical characterization","authors":"Ryo Okinishi ,&nbsp;Taiki Watanabe ,&nbsp;Takanori Ida ,&nbsp;Marty Kwok-Shing Wong ,&nbsp;Tomoki Izumi ,&nbsp;Yousuke Tsuneoka ,&nbsp;Takehiro Tsukada","doi":"10.1016/j.ygcen.2026.114948","DOIUrl":"10.1016/j.ygcen.2026.114948","url":null,"abstract":"<div><div>Natriuretic peptides (NPs) play critical roles in cardiovascular and osmoregulatory homeostasis via guanylyl cyclase-coupled natriuretic peptide receptors (NPRs). Although teleost fishes possess a diverse NP repertoire, their receptor systems remain incompletely understood. In the present study, we identified and characterized a novel <em>npr1</em> paralog (<em>npr1a</em>) in the Japanese eel (<em>Anguilla japonica</em>), a representative of early-diverging lineages. Phylogenetic and synteny analyses revealed that eel <em>npr1a</em> and the previously reported <em>npr1b</em> (also known as <em>npra)</em> are teleost-specific paralogs generated by the third round of whole-genome duplication (3R). Functional analysis using COS-7 cells demonstrated distinct ligand responsiveness: Npr1a exhibited preferential responsiveness to VNP with lower signaling efficacy than Npr1b, whereas Npr1b responded broadly to cardiac NPs (eel ANP-NH₂ &gt; VNP &gt; BNP). <em>In situ</em> hybridization chain reaction revealed marked spatial divergence of these receptors in the eel brain: <em>npr1a</em> was predominantly localized in the parvocellular preoptic nucleus (Pp) and anterior tuberal nucleus (NAT), whereas <em>npr1b</em> was specifically expressed in the area postrema (AP). These regions are located at or near blood–brain barrier-deficient areas. Notably, RT-qPCR data showed that <em>npr1b</em> expression was significantly upregulated in seawater-acclimated eels, while <em>npr1a</em> levels remained stable, indicating distinct transcriptional regulation. Collectively, our findings demonstrate 3R-driven subfunctionalization of Npr1 in the Japanese eel and suggest that the retention of <em>vnp</em> in early-diverging lineages may have facilitated lineage-specific functional diversification of NP receptors during teleost evolution.</div></div>","PeriodicalId":12582,"journal":{"name":"General and comparative endocrinology","volume":"381 ","pages":"Article 114948"},"PeriodicalIF":1.7,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147948221","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Measuring diurnal and lifespan variations of Brain-derived neurotrophic factor in titi monkeys (Plecturocebus cupreus)","authors":"L.A. Meckler ,&nbsp;M.J. Sosnowski ,&nbsp;K.L. Bales","doi":"10.1016/j.ygcen.2026.114936","DOIUrl":"10.1016/j.ygcen.2026.114936","url":null,"abstract":"<div><div>Pair bonding requires substantial neural flexibility to form and maintain complex social relationships in dynamic environments over time. Due to its involvement in synaptic plasticity, Brain-derived neurotrophic factor (BDNF) is a promising candidate for modulating this flexibility, although it has never been studied within the context of pair bonding. The present study sought analytically and biologically validate an enzyme-linked immunosorbent assay (ELISA) to measure BDNF in coppery titi monkeys (<em>Plecturocebus cupreus</em>), a pair bonding non-human primate model. We first validated a commercially available ELISA to detect and measure BDNF in titi monkey serum, and then subsequently characterized the natural decline of BDNF in titi monkeys throughout the day (morning to evening) and across the lifespan (into old age). Titi monkeys showed significantly lower serum levels of BDNF at the end of the day, suggesting a consistent diurnal cycle, and in older age, suggesting age-related decline. This work establishes the foundation for examining BDNF’s role within the behavioral endocrinology of pair bonding.</div></div>","PeriodicalId":12582,"journal":{"name":"General and comparative endocrinology","volume":"381 ","pages":"Article 114936"},"PeriodicalIF":1.7,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147807943","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"PFOA effects on osteoblast differentiation: Involvement of oxidative stress and endocannabinoid receptors","authors":"Fiorenza Sella ,&nbsp;Christian Giommi ,&nbsp;Damiano Carbonari ,&nbsp;Marta Lombó ,&nbsp;Oliana Carnevali","doi":"10.1016/j.ygcen.2026.114932","DOIUrl":"10.1016/j.ygcen.2026.114932","url":null,"abstract":"<div><div>Perfluorooctanoic acid (PFOA), a persistent perfluoroalkyl substance (PFAS), has been implicated in bone mineral density loss and defective osteogenesis. In this study, by employing human fetal osteoblast (hFOB1.19), we investigated whether PFOA interferes with osteoblast differentiation by altering the transcription of genes involved in osteogenesis, and protein levels of oxidative stress defense and cannabinoid receptors (CBs). The hFOB 1.19 were exposed to increasing PFOA concentrations (1–100 µM) for seven days, representing supra-environmental concentration commonly used in mechanistic <em>in vitro</em> studies. Osteogenic markers were then evaluated at transcriptional level together with matrix deposition, and the results were compared to an untreated control group. Exposure to PFOA at 10 µM increased the expression of osteocalcin (<em>BGLAP</em>) encoding for a protein involved in calcium deposition. Catalase (CAT) protein levels were upregulated at 1 µM PFOA, while superoxide dismutase (SOD1) did not change, suggesting a selective antioxidant response to oxidative perturbation. Notably, this increase in CAT correlated with a trend toward <em>RUNX2</em> upregulation, possibly representing a compensatory mechanism to preserve differentiation under oxidative stress. In addition, the highest concentration of PFOA modulated the endocannabinoid system (ECS), reducing CB1 and CB2 protein levels. Despite these molecular changes, Alizarin Red staining revealed a borderline and not statistically significant enhanced calcium deposition only at 50 µM PFOA, suggesting potentially aberrant mineralization. Overall, our findings suggest that PFOA perturbs osteoblast differentiation through oxidative stress-linked mechanisms and CBs modulation, with catalase emerging as a key protective mediator of osteogenic competence under environmental contaminants. Furthermore, the observed dysregulation of CB1 and CB2 receptors indicates that the ECS itself may represent a direct target of PFOA action in osteoblasts.</div></div>","PeriodicalId":12582,"journal":{"name":"General and comparative endocrinology","volume":"380 ","pages":"Article 114932"},"PeriodicalIF":1.7,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147705499","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Motilin in amphibians","authors":"Takio Kitazawa ,&nbsp;Hiroyuki Kaiya","doi":"10.1016/j.ygcen.2026.114917","DOIUrl":"10.1016/j.ygcen.2026.114917","url":null,"abstract":"<div><div>Motilin was first identified as a gastrointestinal (GI) motility-stimulating peptide and was later shown to mediate the gastric migrating motor complexes (MMCs) in several mammals. Motilin and its receptor have also been identified in non-mammalian vertebrates, including birds, reptiles, amphibians and fish. This discovery has prompted comparative studies on its physiological roles in GI motility. This review focused on amphibian motilin and its role in GI contractions. Like those of mammals, birds, and reptiles, amphibian motilin is a 22-amino-acid peptide produced in the mucosa of the upper small intestine. There is structural variation within amphibians: the N-terminal residue is phenylalanine in Caudata (newts and salamanders) but tyrosine in Apoda (caecilians). Interestingly, motilin receptors have been found in Anura (frogs), yet the endogenous motilin remains undiscovered, even though database searches. This discrepancy leaves the physiological role of the motilin system in anurans a subject of ongoing debate. Functional studies reveal that motilin receptors exist in the central nervous system and the GI tract of vertebrates, and demonstrate an evolutionarily related shift in localization. Motilin receptors are restricted to intestinal mucosal cells in fish but expand to GI smooth muscle cells and enteric neurons in amphibians. This marks a pivotal transition toward the regulation of GI motility. This trajectory culminates in birds and mammals, where receptors are present across the mucosa, smooth muscle, and myenteric plexus. However, the mechanisms driving this receptor expansion, the definitive status of motilin in Anuras, and the specific roles of motilin receptor or motilin-like receptor in these species remain unclear. Addressing these questions will provide deeper insights into the evolutionary endocrinology of the gut–brain axis, establishing amphibian motilin research as a compelling frontier.</div></div>","PeriodicalId":12582,"journal":{"name":"General and comparative endocrinology","volume":"380 ","pages":"Article 114917"},"PeriodicalIF":1.7,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147618612","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Understanding thyroid hormone receptor function in controlling developmental timing and rate in Xenopus: A journey from biochemistry and molecular biology to genetics","authors":"Yun-Bo Shi","doi":"10.1016/j.ygcen.2026.114927","DOIUrl":"10.1016/j.ygcen.2026.114927","url":null,"abstract":"<div><div>Anuran metamorphosis has long been used as a model to study thyroid hormone (T3) function during vertebrate development. The cloning of T3 receptor (TR) in the late 1980 s opened a door for using anuran metamorphosis to address some fundamental questions on T3 action in development that were difficult to ask or address in mammalian models. Here, I will review some of the studies ranging from biochemical and molecular investigations to more recent genetic studies that have not only uncovered novel and critical roles of TR in regulating adult organ development and larval tissue resorption/remodeling but also revealed <em>in vivo</em> mechanisms of T3 action. I will focus mainly on the work involving two highly related species, the allotetraploid <em>Xenopus laevis</em> and diploid <em>Xenopus tropicalis</em>, which offer many unique but complementary advantages for <em>in vivo</em> studies of TR function.</div></div>","PeriodicalId":12582,"journal":{"name":"General and comparative endocrinology","volume":"380 ","pages":"Article 114927"},"PeriodicalIF":1.7,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147644789","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"What’s in a name? Nomenclature inconsistencies in the corticotropin-releasing factor/hormone system across time and taxa","authors":"Brett M. Culbert ,&nbsp;Nicholas J. Bernier","doi":"10.1016/j.ygcen.2026.114931","DOIUrl":"10.1016/j.ygcen.2026.114931","url":null,"abstract":"<div><div>The use of clear, consistent, and specific terminology is important for maximizing the accessibility of scientific knowledge across all academic disciplines, including endocrinology. Yet, the nomenclature used to describe the primary hypophysiotropic neuropeptide responsible for centrally regulating rates of corticosteroid synthesis in vertebrates is inconsistent. Researchers use the terms “corticotropin-releasing factor (CRF)” and “corticotropin-releasing hormone (CRH)” at almost equal frequency. While this may seem relatively minor, it highlights broader nomenclature issues that exist within this important neuropeptide family. Indeed, most neuropeptides in this family have had multiple names since their initial discovery and/or are described using different names in different taxa. This creates considerable confusion among students and researchers unfamiliar with this literature. In this review, we provide a historical perspective addressing how and why the nomenclature for these neuropeptides has changed. We also provide context for why some inconsistencies (e.g., CRF vs CRH) will likely continue to persist. Overall, our goal is to increase accessibility and remove barriers which may discourage research on this important neuropeptide family.</div></div>","PeriodicalId":12582,"journal":{"name":"General and comparative endocrinology","volume":"380 ","pages":"Article 114931"},"PeriodicalIF":1.7,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147689704","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Purification and charcterization of a neuropeptide (AN peptide) from starfish, Asterias amurensis","authors":"Mi Jeong Jo ,&nbsp;Hye-Jin Go ,&nbsp;Nam Gyu Park ,&nbsp;Gun-Do Kim","doi":"10.1016/j.ygcen.2026.114926","DOIUrl":"10.1016/j.ygcen.2026.114926","url":null,"abstract":"<div><div>Although neuropeptides have been extensively studied in marine invertebrates, their diversity and physiological roles remain incompletely understood. Starfish is marine echinoderm with a unique water structure, and lives in seas around the world. In this study, neuropeptide was purified from starfish <em>Asterias amurensis</em> and their properties were analyzed. ANP is a muscle-contracting peptide composed of 18 amino acids purified from starfish tube feet. As a result of full-length cDNA analysis, a total of 5 isotypes were identified through post-translational conversion by dibasic cleavage site (KR) and monobasic cleavage site (K). To investigate the potential physiological role of ANP, tissue-specific expression profiles of ANP transcript were checked and it was found to be highly expressed in the nerve cord. <em>In vitro</em> pharmacological assay confirmed that ANP caused contraction in the apical muscle of <em>A. amurensis</em>. Additionally, the effect of <em>in vivo</em> injection on starfish motility revealed that starfish motility was significantly reduced by ANP. These findings suggest that ANP is a neuropeptide involved in the regulation of muscle contraction and locomotor behavior in starfish, providing new insights into the physiological roles of neuropeptides in echinoderms.</div></div>","PeriodicalId":12582,"journal":{"name":"General and comparative endocrinology","volume":"380 ","pages":"Article 114926"},"PeriodicalIF":1.7,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147722564","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}