General and comparative endocrinology最新文献

{"title":"Melatonin suppresses the seasonal estrus in female giant pandas.","authors":"He Huang, Rong Hou, David C Kersey, Jingchao Lan, Zongjin Ye, Yuan Li, Ying Yao, Kailai Cai, Xianbiao Hu, Yuliang Liu","doi":"10.1016/j.ygcen.2025.114827","DOIUrl":"10.1016/j.ygcen.2025.114827","url":null,"abstract":"<p><p>In mammals, the pineal gland secretes melatonin, which serves as a crucial signal for interpreting photoperiod cues. As a seasonal breeder, the giant panda typically mates during the spring. To fully elucidate melatonin's influence on the seasonal estrus of female giant pandas, we conducted an in-depth analysis of urinary hormones. First, we found that urinary melatonin and gonadotropin-releasing hormone (GnRH) levels exhibit distinct seasonal variations over the annual cycle. From January to April, melatonin levels decline sharply from their annual peak, while GnRH levels rise rapidly and remain elevated throughout February, March, and April, precisely corresponding to the giant panda breeding season. Second, during female estrus, the estrogen metabolites peak occurs near the time when melatonin levels drop to their lowest values, and an inverse correlation between melatonin and estrogen metabolites persists both before and after the estrogen metabolites peak. Our analysis of urinary hormones revealed that melatonin exerts a significant suppressive effect on urinary GnRH and estrogen metabolites production prior to the onset of the seasonal estrus in giant pandas. Given the multipotent differentiation capacity of mesenchymal stem cells, we selected cultured giant panda umbilical cord mesenchymal stem cells (UC-MSCs) as an in vitro model for further study. Initially, we characterized the expression of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) in UC-MSCs following GnRH stimulation. Notably, these cells exhibited pituitary-like functional properties, including responsiveness to GnRH and expression of FSH and LH genes, making them suitable for modeling melatonin's effects. Subsequent experiments demonstrated that melatonin suppresses GnRH-induced LH and FSH mRNA expression in UC-MSCs in a dose-dependent manner and higher concentrations of melatonin were particularly effective. Collectively, our study not only elucidates the regulatory effects of melatonin on the seasonal estrous cycle of female giant pandas but also offers valuable new perspectives. These insights can potentially guide the development of conservation strategies for this endangered species, facilitating more targeted and effective efforts to safeguard its population.</p>","PeriodicalId":12582,"journal":{"name":"General and comparative endocrinology","volume":" ","pages":"114827"},"PeriodicalIF":1.7,"publicationDate":"2025-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145232312","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":"Synthesis of sex steroids and expression of sex steroid receptors during gonadal development of the snail-eating turtle Malayemys macrocephala (Gray, 1859)","authors":"Rangsima Pewphong ,&nbsp;Gen Watanabe ,&nbsp;Kentaro Nagaoka ,&nbsp;Jirarach Kitana ,&nbsp;Tongchai Thitiphuree ,&nbsp;Noppadon Kitana","doi":"10.1016/j.ygcen.2025.114826","DOIUrl":"10.1016/j.ygcen.2025.114826","url":null,"abstract":"<div><div>Prior studies on the freshwater turtle <em>Malayemys macrocephala</em> showed that the incubation temperature influenced somatic and gonadal development, supporting temperature-dependent sex determination. This study aimed to examine the onset of steroidogenesis and expression of steroid receptors during gonadal development of <em>M. macrocephala</em>. Embryos at the sexually undifferentiated gonad (stages 14–16), differentiating gonad (stages 17–22), and differentiated gonad (stages 23–25) stages reared at the male- and female-producing temperatures (26 °C and 32 °C, respectively) were examined. Gonads were assessed for steroidogenic potential by immunofluorescence staining using antibodies against 3β-hydroxysteroid dehydrogenase (3β-HSD), 17β-hydroxysteroid dehydrogenase (17β-HSD), and P450 aromatase (P450arom), as well as the androgen receptor (AR) and estrogen receptor α (ERα). In males, expression of these steroidogenic enzymes and steroid receptors were found as follows: 3β-HSD at stages 14–22, 17β-HSD at stages 14–25, and AR at stages 17–25. In females, the expression was as follows: 3β-HSD and 17β-HSD at stages 14–22, P450arom at stages 19–25, and ERα at stages 19–25. Overall, the results suggest that in gonadal development of <em>M. macrocephala</em>: 3β-HSD plays a role as a key enzyme in the biosynthesis of sex steroids, 17β-HSD and the AR play roles in testis development, and P450arom and the ERα are involved in ovary development.</div></div>","PeriodicalId":12582,"journal":{"name":"General and comparative endocrinology","volume":"374 ","pages":"Article 114826"},"PeriodicalIF":1.7,"publicationDate":"2025-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145232266","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":"Does motilin primarily regulate gastrointestinal motility in fish?","authors":"Takio Kitazawa ,&nbsp;Hiroyuki Kaiya ,&nbsp;Shuangyi Zhang","doi":"10.1016/j.ygcen.2025.114824","DOIUrl":"10.1016/j.ygcen.2025.114824","url":null,"abstract":"<div><div>Motilin (MLN) is a gut motility-stimulating peptide hormone that regulates the gastric migrating motor complex in humans, dogs, monkeys, and house musk shrews (<em>Suncus</em>). MLN and its receptors are found not only in mammals but also in other vertebrates (birds, reptiles, amphibians, and fish). This review focuses on the physiological roles of MLN in fish. Fish MLNs are produced in the mucosa of the upper small intestine. MLNs in amphibians, reptiles, birds, and mammals are 22-amino-acid peptides with phenylalanine at the first position of the N-terminus, except for reptile MLNs. In contrast, fish MLNs are shorter, and the N-terminal starts with histidine instead of phenylalanine. The function of MLN can be inferred from the distribution of MLN receptors. MLN receptors are commonly expressed in the central nervous system and gastrointestinal (GI) tract of fish, as in mammals. In the central nervous system, MLN is thought to be involved in the regulation of feeding and drinking. However, MLN receptors in the fish GI tract are limited to the intestinal mucosa, and MLN fails to induce contraction in the fish GI tract. In amphibians, birds, and mammals, the expression of MLN receptors extends to GI smooth muscles and enteric neurons and is involved in the regulation of GI motility. These findings suggest that MLN is not a regulator of GI motility in fish, but instead regulates the functions of intestinal mucosal cells and central neurons.</div></div>","PeriodicalId":12582,"journal":{"name":"General and comparative endocrinology","volume":"373 ","pages":"Article 114824"},"PeriodicalIF":1.7,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145182074","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":"Impact of artificial light at night and night shift work on brain functions and metabolism","authors":"Horst-Werner Korf ,&nbsp;Nora Bittner ,&nbsp;Svenja Caspers ,&nbsp;Charlotte von Gall","doi":"10.1016/j.ygcen.2025.114822","DOIUrl":"10.1016/j.ygcen.2025.114822","url":null,"abstract":"<div><div>The present review focusses on artificial light at night (ALAN) and night shift work (NSW) as examples for chronodisruption occurring in modern societies. Chronodisruption can lead to significant sleep and health problems and increase the risk of chronic diseases. This pathomechanism involves endocrine systems (glucocorticoids, melatonin). ALAN affects at least 80% of mankind and disturbs physiological, biological and behavioral processes in wildlife. In humans, the nighttime use of illuminated screens contributes to ALAN, with as yet unforeseeable consequences for body and brain. Acute continuous light exposure triggers pro-inflammatory responses in the brain which may make it more vulnerable to additional aversive stimuli. Moreover, acute continuous light impairs cognitive function and synaptic plasticity and leads to an increase in corticosterone, a stress hormone and an important mediator in the circadian system. Several studies on NSW reported increased risk for sleep disorders, cancer, cardiovascular disease, type 2 diabetes, obesity, and depression. However, objective imaging analyses supplemented by neuropsychological examinations revealed that NSW has only minor effects on brain functions. Moreover, a recent study showed that NSW was not accompanied by metabolic, cardiovascular or immunological problems. In conclusion, ALAN may be considered a relevant factor influencing human health and biodiversity and should be avoided whenever possible. Studies on the effects of NSW report varying results. This may be due to differences in light intensity during shift, the quality of the occupational health service and the shift work schedule. All these aspects need further investigations to prevent or mitigate the health risk of NSW.</div></div>","PeriodicalId":12582,"journal":{"name":"General and comparative endocrinology","volume":"373 ","pages":"Article 114822"},"PeriodicalIF":1.7,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145112598","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":"Aldosterone increased by chronic unpredictable mild stress damages epididymal sperm quality in young rats","authors":"Tonantzi Guadalupe Osorio Pérez ,&nbsp;Eliut Pérez-Sánchez ,&nbsp;Vanessa Guadalupe Nolasco Garduño ,&nbsp;Adriana Corona-Pérez ,&nbsp;María de Lourdes Arteaga Castañeda ,&nbsp;Rosa Angélica Lucio ,&nbsp;Jorge Rodríguez-Antolín ,&nbsp;Leticia Nicolás-Toledo","doi":"10.1016/j.ygcen.2025.114823","DOIUrl":"10.1016/j.ygcen.2025.114823","url":null,"abstract":"<div><div>In young rats, aldosterone concentration increases in response to stress. Aldosterone can decrease testosterone production. We hypothesized that aldosterone impairs sperm quality, and that this impairment is reversible with 50 mg/kg of eplerenone in young rats. Forty-two young male Wistar rats (51 days old) were divided into six groups: Control, Control + vehicle (C + Veh), chronic unpredictable mild stress (CUMS), and CUMS + eplerenone at three concentrations: 25, 50, and 100 mg/kg bw, a selective aldosterone blocker (CUMS + EP) (n = 7 per each). On postnatal day 51, eplerenone was administered orally via gastric tube 2 h before the start of the stress test. The CUMS paradigm was administered once daily at various times, without repeating the stressor, over a four-week period. We evaluated the effects of chronic stress on serum testosterone concentrations, oxidative stress, apoptosis, and sperm quality. The CUMS group exhibited low testosterone levels and poor epididymal sperm quality. Compared to the CUMS group, the 50 mg/kg dose of eplerenone demonstrated significant improvements in sperm motility (28.8 %), sperm viability (36.9 %), and sperm concentration (58.9 %). In the CUMS context, the 100 mg/kg dose was toxic because it induced oxidative stress and apoptosis. Aldosterone negatively affects epididymal sperm quality by reducing testosterone-induced sperm motility, viability, and concentration. Aldosterone impairs sperm quality, which is reversible with 50 mg/kg of eplerenone. The prevention by eplerenone supports our hypothesis.</div></div>","PeriodicalId":12582,"journal":{"name":"General and comparative endocrinology","volume":"373 ","pages":"Article 114823"},"PeriodicalIF":1.7,"publicationDate":"2025-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145148650","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":"Expression of the estrogen receptor gene across the life cycle in the polychaete, Capitella teleta","authors":"A.M. Murillo ,&nbsp;A.R. Lanza ,&nbsp;M. Hendershot ,&nbsp;E.V.W. Setton ,&nbsp;E.C. Seaver ,&nbsp;J.Y. Wilson","doi":"10.1016/j.ygcen.2025.114821","DOIUrl":"10.1016/j.ygcen.2025.114821","url":null,"abstract":"<div><div>Vertebrate estrogen receptors (<em>ER</em>s; NR3A subfamily genes) are essential for regulating multiple biological processes in vertebrates. However, little is known about <em>ER</em>s (NR3D subfamily genes) in invertebrates. <em>Capitella teleta</em> is a marine polychaete with a single <em>ER</em> gene that is ligand-activated with low concentrations of estradiol <em>in vitro</em>; yet the physiological role of this receptor is unclear. We used whole-mount <em>in situ</em> hybridization to investigate spatial and temporal expression patterns of the <em>ER</em> in larval stages and RT-qPCR to detect temporal ER gene expression patterns across age and sex in juvenile and adults. The <em>ER</em> gene was expressed in the brain and foregut across multiple larval stages, suggesting a role in brain and gastrointestinal development. Whole-body juvenile <em>ER</em> gene expression was similar between two and six weeks of age. <em>ER</em> expression was similar across sex between head fragments, gastrointestinal systems, or whole bodies of sexually mature worms. These data show that the <em>ER</em> does not exhibit a sexually dimorphic expression as is stereotypical in vertebrates, and suggests that the ER may may not play a big role in sexual maturation in <em>C. teleta</em>. Collectively, <em>ER</em> is expressed across multiple life stages and suggests a role in brain and foregut development, and possibly a gastrointestinal function in adults. This study aids in uncovering the physiological functions of ER in lophotrochozoans.</div></div>","PeriodicalId":12582,"journal":{"name":"General and comparative endocrinology","volume":"373 ","pages":"Article 114821"},"PeriodicalIF":1.7,"publicationDate":"2025-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145118076","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":"Identification and functional characterization of relaxin-like gonad stimulating peptide in the sea cucumber, Stichopus horrens","authors":"Tyler R. Goodearly ,&nbsp;An Wirth-Yap ,&nbsp;Bradley K. Fox ,&nbsp;Hidekazu Katayama ,&nbsp;Andre P. Seale","doi":"10.1016/j.ygcen.2025.114819","DOIUrl":"10.1016/j.ygcen.2025.114819","url":null,"abstract":"<div><div>In the state of Hawaiʻi, there is rising interest in the culture of native sea cucumbers, such as <em>Stichopus horrens;</em> however, current production is hindered by a limited understanding of their reproductive biology. Originally described in starfish, relaxin-like gonad stimulating peptide (RGP) has been characterized and used to induce oocyte maturation and spawning in sea cucumbers. For the first time using <em>S. horrens</em> specifically, we identified the RGP (Sh-RGP) coding sequence through <em>de novo</em> transcriptomics<em>,</em> synthesized the mature peptide, and investigated its role in inducing oocyte maturation <em>in vitro</em>, and spawning <em>in vivo</em>. The Sh-RGP precursor gene encodes a single mature peptide composed of two amino acid chains. The B- and A-chains contain two and four cysteine residues, respectively, resulting in an intra-chain linkage on the A-chain and two disulfide connections between the two chains. A synthetic Sh-RGP was produced from solid-phase peptide synthesis, bonded, and isolated by reverse-phase HPLC. A tissue distribution analysis revealed that <em>shrgp</em> mRNA expression is highest (<em>P</em> <!-->&lt;<!--> <!-->0.001) in the neural ring. <em>In vitro</em>, Sh-RGP (0.1–10 μM) induced germinal vesicle breakdown in oocytes incubated with gonadal tissue in time and concentration-dependent fashions. When injected with Sh-RGP (∼4.5 μg/kg body weight), all mature male and female sea cucumbers spawned within 39 min of treatment. Overall, these results indicate that Sh-RGP induces oocyte maturation and spawning and provide a framework for integrating transcriptomics and functional assays to elucidate and validate endogenous species-specific reproductive hormones that can be used to address barriers in sea cucumber aquaculture.</div></div>","PeriodicalId":12582,"journal":{"name":"General and comparative endocrinology","volume":"373 ","pages":"Article 114819"},"PeriodicalIF":1.7,"publicationDate":"2025-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145102732","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":"Photoperiod-dependent expression of ‘Cocaine- and amphetamine-regulated transcript peptide’ and ‘Neuropeptide Y’ in the brain of anuran Minervarya syhadrensis","authors":"Ketaki Shetye ,&nbsp;Sneha Sagarkar ,&nbsp;Swapnil Shewale ,&nbsp;Amul Sakharkar ,&nbsp;Shobha Bhargava ,&nbsp;Richa Ashma","doi":"10.1016/j.ygcen.2025.114820","DOIUrl":"10.1016/j.ygcen.2025.114820","url":null,"abstract":"<div><div>Anurans exhibit diurnal behavioral patterns; however, the expression of neuropeptides that modulate these activities remains unexplored. This study investigates day-night expression patterns of Cocaine- and Amphetamine-Regulated Transcript Peptide (CARTp) and Neuropeptide Y (NPY) in the brain of nocturnal frog, <em>Minervarya syhadrensis</em>. Frogs were sacrificed at different timepoints (1) under normal day-night conditions (2) after exposure to 24 h darkness and (3) 24 h light. Brain tissues, including the olfactory system, were collected for immunohistochemical analysis. Photoperiod-dependent alterations in expression of CART and NPY were observed in various brain regions. According to cosine analysis, the oscillation was seen only in the olfactory epithelium (OE) with maxima at 11:00. In anteroventral tegmentum (AV), CARTp and NPY expression were highest at midnight. In few brain regions, NPY or CARTp oscillations were observed. NPY oscillations were seen in preoptic area (POA), with a peak at noon, and in suprachiasmatic nucleus (SCN), anterior ventral hypothalamus (AvHy), and nucleus isthmus (NI) highest expression was at midnight. In Edinger-Westphal nucleus (EW) and posterior ventral hypothalamus (PvHy) CARTp upregulation was observed at midnight. CARTp fluctuated in OE, PvHy, and EW on light exposure, while changes in NPY expression were seen in OE, POA and SCN. Photoperiod-dependent fluctuations in both peptides were noted in OE and AV. While on exposure to darkness, CARTp expression decreased in AV, PvHy, and EW, and NPY expression was affected in AV, POA, SCN, AvHy, and NI. These results suggest neuropeptides in anurans exhibit photoperiod-dependent differential expression, potentially regulating physiological functions and behavioral patterns.</div></div>","PeriodicalId":12582,"journal":{"name":"General and comparative endocrinology","volume":"373 ","pages":"Article 114820"},"PeriodicalIF":1.7,"publicationDate":"2025-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145091652","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":"Corticotropin-releasing hormone enhances the responsivity of macrophages to inflammation in zebrafish","authors":"Joeri van Heijningen ,&nbsp;Laura H.M. van der Pluijm ,&nbsp;Marcel J.M. Schaaf ,&nbsp;Erin Faught","doi":"10.1016/j.ygcen.2025.114815","DOIUrl":"10.1016/j.ygcen.2025.114815","url":null,"abstract":"<div><div>The immunomodulatory role of steroid stress hormones, such as cortisol, are well characterized; however, less is known about how other stress hormones affect the immune system. Release of central corticotropin-releasing hormone (Crh) will result in an indirect anti-inflammatory effect due to the stimulation of cortisol production. Conversely, peripheral release of Crh is thought to directly exhibit proinflammatory effects on leukocytes. This suggests that the peripheral Crh system promotes inflammation, rather than suppresses it, but the molecular mechanisms are not well defined. To test the hypothesis that Crh will stimulate immune function, we used the zebrafish animal model and assessed leukocyte migration towards a wound as a readout of inflammatory capacity. We show that not only is <em>crhr1</em> regulated during inflammation, but that it directly modulates the leukocyte population localized to a wound site. In particular, it enhances pro-inflammatory macrophage recruitment through the Cxcr3.2/Cxcr11aa signalling axis. Taken together, this work further contributes to our understanding of how Crh, and stress as a whole, can impact immune system function.</div></div>","PeriodicalId":12582,"journal":{"name":"General and comparative endocrinology","volume":"373 ","pages":"Article 114815"},"PeriodicalIF":1.7,"publicationDate":"2025-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145074823","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":"Hair cortisol as an indicator of chronic stress in Eurasian otters (Lutra lutra): Evaluating influencing variations","authors":"Jee Hyun Kim ,&nbsp;Hyejin Kang ,&nbsp;Bong Kyun Kim ,&nbsp;Mi-Sook Min ,&nbsp;Seung Aee Ma ,&nbsp;Je-Yoel Cho","doi":"10.1016/j.ygcen.2025.114816","DOIUrl":"10.1016/j.ygcen.2025.114816","url":null,"abstract":"<div><div>Glucocorticoids such as cortisol are secreted via the HPA axis to maintain homeostasis and respond to stress, but chronic over-activation can impair health and survival. Cortisol accumulation in the hair is particularly useful because it reflects long-term stress, making it a valuable physiological indicator for species conservation and management. However, as variables such as housing conditions, age class, sex, hair color, and disease can affect hair cortisol concentration (HCC), ignoring these variables may lead to inaccuracies in chronic stress evaluation. This study measured HCCs in 33 Eurasian otters (<em>Lutra lutra</em>), an endangered species, to examine whether housing type (wild vs. captive), age, and sex affect HCCs. The results showed that juveniles had significantly higher HCCs than adults, suggesting that age may be a factor influencing HCC. However, no significant differences in HCC were found with respect to sex or housing type. Additionally, two of the individuals with exceptionally high HCC were confirmed to have been affected by disease. We propose that standardizing age class in HCC analysis is necessary, and that other important factors potentially influencing HCC variability should also be considered. In particular, disease has been suggested as a possible factor affecting HCC, and such factors may have an even greater impact on HCC variability. Although no significant differences were found regarding housing type and sex, these factors may be more clearly identified through future studies involving a broader range of housing environments and a larger sample size. However, despite the potential of HCC as a promising indicator of long-term stress, a limitation of this study is that its physiological validity has not yet been sufficiently verified in Eurasian otters. Therefore, the results of this study should be interpreted with caution. Nevertheless, by analyzing key factors influencing HCC, this study provides important foundational data for understanding the effects of housing type, sex, and age on long-term stress assessment.</div></div>","PeriodicalId":12582,"journal":{"name":"General and comparative endocrinology","volume":"373 ","pages":"Article 114816"},"PeriodicalIF":1.7,"publicationDate":"2025-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145069432","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}