General and comparative endocrinology最新文献

{"title":"Cortisol production by interrenal cells in rainbow trout (Oncorhynchus mykiss) is stimulated by 5-HT₄ receptor activation.","authors":"Michael Tea, Laurence E Dionne-Wilson, Marie-Ève Bélair-Bambrick, Kathleen M Gilmour","doi":"10.1016/j.ygcen.2025.114694","DOIUrl":"https://doi.org/10.1016/j.ygcen.2025.114694","url":null,"abstract":"<p><p>Although serotonin (5-HT) can stimulate the hypothalamic-pituitary-interrenal (HPI) axis in fishes, the sites of 5-HT action and the receptor subtypes involved remain unclear. Therefore, the present study identified potential sites of 5-HT action within the HPI axis of rainbow trout, Oncorhynchus mykiss, and examined which of three 5-HT receptor subtypes mediated effects of 5-HT on cortisol production. Expression of the receptors 5htr1a, 5htr2 and 5htr4 was detected at all three levels of the HPI axis, with significantly higher transcript abundance in the preoptic area (POA) of the brain than in the pituitary or head kidney. Administration of 300nmol kg^-1 5-HT, but not 30nmol kg^-1, to cannulated rainbow trout significantly increased circulating cortisol. Despite this cortisol response, no specific effects of 5-HT administration on POA transcript abundance of corticotropin-releasing factor (crf) or circulating adrenocorticotropic hormone (ACTH) concentrations were detected. To assess the direct actions of 5-HT on cortisol production, head kidney tissue was incubated in vitro with 5-HT or selective 5-HT receptor agonists. Neither the 5-HT_1A receptor agonist 8-hydroxy-2-(di-n-propylamino)-tetralin (8-OH-DPAT) nor the 5-HT₂ receptor agonist α-methyl-5-hydroxytryptamine maleate (α -methyl 5-HT) stimulated cortisol production. However, head kidney cortisol production was significantly increased by the 5-HT₄ receptor agonist cisapride, an effect that was eliminated when tissue was incubated with a combination of cisapride and the 5-HT₄ receptor antagonist GR125487. Collectively, these data support a role for 5-HT in HPI axis activation in rainbow trout, and suggest that effects of 5-HT in the head kidney are mediated by the 5-HT₄ receptor.</p>","PeriodicalId":12582,"journal":{"name":"General and comparative endocrinology","volume":" ","pages":"114694"},"PeriodicalIF":2.1,"publicationDate":"2025-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143515435","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":"Evaluating variation in acute stress response in captive Wood Ducks (Aix sponsa)","authors":"Lindsey J. Broadus ,&nbsp;Mitchell G. Hinton ,&nbsp;Thomas P. Hahn ,&nbsp;John C. Wingfield ,&nbsp;John M. Eadie ,&nbsp;Maja M. Makagon","doi":"10.1016/j.ygcen.2025.114687","DOIUrl":"10.1016/j.ygcen.2025.114687","url":null,"abstract":"<div><div>Acute stress response has been linked to body condition and associated with the allocation of finite energy resources in wild, free-living birds. However, the relationship between the body condition of individuals and the acute stress response is less clear for birds kept in captive settings, where energy resources are abundant and readily available. We evaluated how individual variation in body condition, reflected as body mass, relates to the acute stress response in adult captive Wood Ducks (<em>Aix sponsa</em>) hatched from eggs collected in the wild and reared in captivity while birds were fed <em>ad libitum,</em> in and out of the breeding season. We determined plasma corticosterone (CORT) levels from blood collected within 3 min of capture and at 10, 30, and 60 min post-capture from 28 ducks during spring and fall, in and out of breeding season. Body condition measurements were recorded once for each bird in early spring. The effects of body mass, age, and time of year (in vs. out of breeding season) on total and maximum CORT secreted were analyzed in Generalized Linear Mixed Models (GLMM). No relationships between age, body mass, and total or maximum CORT were found. There was a significant difference in response in and out of the breeding season for total CORT (<em>p</em> &lt; 0.01) and maximum CORT (<em>p</em> &lt; 0.001), with a higher response during the breeding season. Measures of individual responses for total (<em>p</em> = 0.001) and maximum CORT (<em>p</em> &lt; 0.01) were consistent across seasons. Baseline CORT levels were consistently low, with 53.6 % and 78.6 % of the samples below the detection limit during and outside of breeding season, respectively. These results highlight differences in baseline CORT maintenance compared to studies on wild Wood Ducks, potentially relating to environmental differences such as unlimited food supply and protection from predators in captivity. Additionally, we found that captive birds maintain seasonal variation in acute stress response, which reflects some trends found in wild birds, although more research across multiple seasons is warranted. We also found that some captive Wood Ducks continue to increase CORT secretion at the end of the 60 min handling period, indicating that longer handling times may reveal differences in total CORT secreted. Further investigation should be done to assess the costs and benefits of variation in body condition in terms of coping ability across life stages.</div></div>","PeriodicalId":12582,"journal":{"name":"General and comparative endocrinology","volume":"364 ","pages":"Article 114687"},"PeriodicalIF":2.1,"publicationDate":"2025-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143472348","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of blocking transforming growth factor-β/Activin-Myostatin signaling on the expression of ecdysteroid metabolism and responsive genes in the crustacean molting gland (Y-organ)","authors":"Samiha A.M. Benrabaa ,&nbsp;Donald L. Mykles","doi":"10.1016/j.ygcen.2025.114675","DOIUrl":"10.1016/j.ygcen.2025.114675","url":null,"abstract":"<div><div>Molting in decapod crustaceans is controlled by ecdysteroids synthesized and secreted by the molting gland, or Y-organ (YO). The YO undergoes phenotypic changes in ecdysteroid production that drive molt cycle stage transitions; these are the basal, activated, committed, and repressed states in the intermolt, early premolt, mid- and late premolt, and postmolt stages, respectively. Reduced secretion of molt-inhibiting hormone (MIH) by a neurosecretory center in the eyestalk ganglia activates the YO and the animal transitions to early premolt. During premolt, transforming growth factor-beta (TGFβ)/Activin-Myostatin (Mstn) signaling mediates the transition of the YO from the activated to the committed state, as SB431542 blocks this transition. In the blackback land crab, <em>Gecarcinus lateralis</em>, the YO expresses genes involved in ecdysteroid synthesis (<em>Gl-NADK</em>, <em>Gl-ALAS</em> and Halloween genes <em>Gl-Nvd</em>, <em>Gl-Spo</em>, <em>Gl-Phm</em>, <em>Gl-Dib</em>, and <em>Gl-Sad</em>) and catabolism (<em>Gl-CYP18a1</em>); ecdysteroid signaling (ecdysteroid responsive genes <em>Gl-EcR</em>, <em>Gl-RXR</em>, <em>Gl-Br-C</em>, <em>Gl-HR3</em>, <em>Gl-HR4</em>, <em>Gl-E74</em>, <em>Gl-E75</em>, and <em>Gl-Ftz-f1</em>); and <em>Gl-FOXO</em>. Intermolt adult <em>G. lateralis</em> were induced to molt by eyestalk ablation (ESA) and injected with either dimethyl sulfoxide (DMSO) vehicle (control) or SB431542 in DMSO (experimental) at Day 0. ESA increased hemolymph ecdysteroid titer at 1, 3, and 5 days post-ESA in both control and experimental groups, indicating that SB431542 had no effect on YO activation. Ecdysteroid titer did not increase further in the experimental group at 7 and 14 days post-ESA, indicating that SB431542 prevented transition of the YO to the committed state. ESA with or without SB431542 had no effect on the mRNA levels of the eight ecdysteroid metabolism genes, seven of the eight ecdysteroid responsive genes (the only exception was <em>Gl-E74</em> at 1 day post-ESA), and <em>Gl-FOXO</em> at 1, 3, and 5 days post-ESA. Compared to the control group, SB431542 lowered the mRNA level of <em>Gl-Nvd</em> at 7 and 14 days post-ESA and mRNA levels of <em>Gl-Spo</em>, <em>Gl-Phm</em>, <em>Gl-Dib</em>, <em>Gl-Sad, Gl-CYP18a1, Gl-ALAS</em>, <em>Gl-NADK, Gl-EcR</em>, <em>Gl-RXR</em>, <em>Gl-Br-C</em>, and <em>Gl-FOXO</em> at 14 days post-ESA. SB431542 had no effect on the mRNA levels of <em>Gl-HR3 Gl-HR4, Gl-E74, Gl-E75</em> and <em>Gl-Ftz-f1</em>. These results suggest that TGFβ/Activin-Mstn signaling maintains the mRNA levels of genes needed for increased ecdysteroid synthesis and signaling in the committed YO during mid- and late premolt.</div></div>","PeriodicalId":12582,"journal":{"name":"General and comparative endocrinology","volume":"362 ","pages":"Article 114675"},"PeriodicalIF":2.1,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143348438","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":"An insight into the molecular mechanisms of persistent organic pollutants (POPs) mediated dysregulation of glucose and lipid homeostasis in Heteropneustes fossilis","authors":"Shubhendu Shekhar Ray,&nbsp;Archisman Mahapatra,&nbsp;Priya Gupta,&nbsp;Anjali Suman,&nbsp;Rahul Kumar Singh","doi":"10.1016/j.ygcen.2025.114670","DOIUrl":"10.1016/j.ygcen.2025.114670","url":null,"abstract":"<div><div>The study emphasises how ubiquitous persistent organic pollutants (POPs) are and how terrible they are for the environment, specifically because of their tendency to build up in living things and cause a variety of health problems, including diabetes, obesity, and cardiovascular disorders. Due to POPs affinity for lipid-rich tissues, they accumulate in a variety of organs, where they cause metabolic disruption and initiate various anabolic pathways. Studies that use fish as a model organism clarify the metabolic effects of POPs, demonstrating non-adipose lipid accumulation and abnormal glucose homeostasis. Further research on molecular mechanisms shows that POPs interact with gluconeogenic enzymes, causing blood glucose levels to rise. These results are supported by histological and biochemical examinations of fish exposed to POPs, which show changes in lipid composition and cause cellular damage. Molecular docking computational studies demonstrate POPs propensity for binding to gluconeogenic enzymes, providing insight into their potential to promote hyperglycaemia. This study provides a thorough summary of POPs harmful effects on organisms, highlighting their molecular and toxicological, impacts while arguing for better knowledge of their toxicity to vertebrates’ developing embryos.</div></div>","PeriodicalId":12582,"journal":{"name":"General and comparative endocrinology","volume":"362 ","pages":"Article 114670"},"PeriodicalIF":2.1,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143065101","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":"Pharmacological function of melanocortin-3 receptor in goldfish (Carassius auratus)","authors":"Ming-Xing Yao ,&nbsp;Yu-You Du ,&nbsp;Hao-Lin Mo ,&nbsp;Yasmeen Gul ,&nbsp;Qing-Chuan Song ,&nbsp;Hui-Xia Yu ,&nbsp;Ke-Xin Liu ,&nbsp;Li-Xin Wang ,&nbsp;Yang Li","doi":"10.1016/j.ygcen.2025.114662","DOIUrl":"10.1016/j.ygcen.2025.114662","url":null,"abstract":"<div><div>The melanocortin-3 receptor (MC3R) was recognized for its critical role in energy metabolism and inflammatory responses in mammals; however, its functions in fish remain poorly understood. This study characterized the <em>mc3r</em> gene in goldfish, investigating its sequence, tissue distribution, and pharmacological responses. The coding sequence of goldfish <em>mc3r</em> was 975 bp, translating to a 325-amino-acid protein typical of G protein-coupled receptors, with notable conservation across cyprinids. Quantitative PCR analysis revealed high expression levels in the brain. Luciferase assays demonstrated that various agonists, particularly NDP-MSH and ACTH (1–24), effectively activated the cAMP and MAPK/ERK signaling pathways. Furthermore, all agonists tested (α-MSH, β-MSH, ACTH (1–24), and NDP-MSH) significantly inhibited NF-κB signaling, correlating with their activation of cAMP. These findings enhanced our understanding of the melanocortin system’s role in regulating energy metabolism and inflammatory processes in teleost fish.</div></div>","PeriodicalId":12582,"journal":{"name":"General and comparative endocrinology","volume":"362 ","pages":"Article 114662"},"PeriodicalIF":2.1,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142964485","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 expression analysis of three gonadotropin-releasing hormone genes in the lined seahorse (Hippocampus erectus)","authors":"Zijian Lu ,&nbsp;Shiming Wan ,&nbsp;Qiang Lin ,&nbsp;Huixian Zhang","doi":"10.1016/j.ygcen.2025.114673","DOIUrl":"10.1016/j.ygcen.2025.114673","url":null,"abstract":"<div><div>Gonadotropin-releasing hormone (GnRH) plays a crucial role in regulating reproductive behavior in vertebrates through the hypothalamus-pituitary-gonad (HPG) axis. Seahorses exhibit unique male pregnancy behavior, making them an interesting subject for investigating the regulatory mechanisms behind this behavior. In this study, we focused on the lined seahorse (<em>Hippocampus erectus</em>) and obtained the full-length cDNA sequences of three <em>GnRH</em> genes: <em>GnRH1</em>, <em>GnRH2</em>, and <em>GnRH3</em>. Notably, we newly identified <em>GnRH1</em>, filling a gap in previous research that had overlooked this subtype. Through a homologous analysis, we found that the core peptide of GnRH1 in lined seahorses is not common in teleosts, while the core peptides of GnRH2 and GnRH3 are conserved. Real-time PCR was performed to determine the tissue expression patterns of these <em>GnRH</em> genes. Our results showed that all three genes were predominantly expressed in the brain, albeit in different regions. Specifically, <em>GnRH1</em> was mainly expressed in the hypothalamus, <em>GnRH2</em> in the optic tectum, and <em>GnRH3</em> in the telencephalon. Expression dynamics indicated a progressive decrease in <em>GnRH2</em> and a significant surge in <em>GnRH3</em> during gonadal development, hinting at an alternating regulatory function. Moreover, <em>GnRH1</em> and <em>GnRH3</em> expression levels were considerably higher during pregnancy compared to those in pre-pregnancy and post-pregnancy stages, underscoring their critical role in modulating male pregnancy behavior in lined seahorses. Our findings provide insights into the complex interplay of GnRH subtypes in regulating reproductive processes, particularly in the context of male pregnancy behavior in seahorses.</div></div>","PeriodicalId":12582,"journal":{"name":"General and comparative endocrinology","volume":"362 ","pages":"Article 114673"},"PeriodicalIF":2.1,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143364364","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":"The role of the opioid peptide dynorphin during the seasonal and gonadotropin-induced ovarian recrudescence in the gecko","authors":"Ananya Ganeyan,&nbsp;C.B. Ganesh","doi":"10.1016/j.ygcen.2025.114684","DOIUrl":"10.1016/j.ygcen.2025.114684","url":null,"abstract":"<div><div>The aim of the current investigation was to elucidate the influence of the opioid peptide dynorphin-A (DYN) on the reproductive axis during breeding and non-breeding phases of the ovarian cycle in the gecko <em>Hemidactylus frenatus.</em> During the recrudescence phase, administration of a high dose of DYN (10 µg/0.1 ml saline) caused a significant reduction in the numbers of oogonia and primary oocytes in the germinal bed, compared to those of the initial controls or experimental controls. Administration of a low (2 µg DYN/0.1 ml saline) or high dose of DYN did not affect the follicular development up to stage IV, but there were no stage V (vitellogenic) follicles in the ovary in contrast to their presence in the experimental controls. Furthermore, there was a significant reduction in gonadotropin-releasing hormone-immunoreactive (GnRH-ir) content in the median eminence (ME) and pars distalis of the pituitary gland (PD) in low or high doses of DYN-treated lizards. During the regression phase, treatment with follicle-stimulating hormone (FSH) resulted in the appearance of stage IV and V follicles, in contrast to their absence in initial controls and treatment controls. However, treatment with 10 µg DYN + FSH did not promote the development of these follicles. In addition, <em>in vitro</em> treatment of DYN significantly inhibited ovarian levels of estradiol. Collectively, these findings reveal an inhibitory influence of DYN on the seasonal ovarian recrudescence, possibly mediated through the suppression of GnRH release into the ME and PD and directly at the level of the ovary by impairment in steroidogenesis and vitellogenic follicular growth in the gecko.</div></div>","PeriodicalId":12582,"journal":{"name":"General and comparative endocrinology","volume":"363 ","pages":"Article 114684"},"PeriodicalIF":2.1,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143429849","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":"Neuromodulation in the fish brain for reproductive success","authors":"Chie Umatani","doi":"10.1016/j.ygcen.2024.114658","DOIUrl":"10.1016/j.ygcen.2024.114658","url":null,"abstract":"<div><div>In most teleosts, appropriate sexual behaviors and sexual maturation are essential for reproductive success. Most fish display their unique behavioral patterns for mating. These behaviors are thought to be regulated in the brain by sex steroid hormones since sexual behaviors are displayed only by sexually mature fish. In addition, recent studies have reported that neuropeptides, which are peptides released from neurons and modulate neural activities via their specific receptors in the brain, also play a key role in regulating sexual behavior. On the other hand, not only sexual behavior but also feeding behavior is important for reproductive function since sexual maturation requires sufficient nutrition. Especially feeding-related peptides, a type of neuropeptides, are thought to modulate feeding behavior. Thus, it is conceivable that neuropeptides are crucial modulators in the brain for reproductive success. This review summarizes recent advances in the knowledge of the neuromodulatory systems involved in sexual and feeding behaviors by neuropeptides and gonadal hormones.</div></div>","PeriodicalId":12582,"journal":{"name":"General and comparative endocrinology","volume":"363 ","pages":"Article 114658"},"PeriodicalIF":2.1,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142863640","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":"The S6 kinase gene in the fruit fly, Drosophila melanogaster, is essential for metabolic regulation","authors":"Jéssica Paloma Álvarez-Rendón ,&nbsp;Juan Rafael Riesgo-Escovar","doi":"10.1016/j.ygcen.2025.114672","DOIUrl":"10.1016/j.ygcen.2025.114672","url":null,"abstract":"<div><div>The S6 kinase (S6K) enzyme phosphorylates the S6 ribosomal protein, promoting protein translation and growth. Here we investigated in flies whether hypomorphic conditions in S6K affect intermediate metabolism and oxidative homeostasis, besides carbohydrates and growth. We also employed partial activation of the nuclear factor 2 erythroid related factor 2 (Nrf2) in a S6K hypomorphic background and controls. S6K is activated by the target of rapamycin (TOR) kinase, a key kinase regulating metabolism, downstream of the insulin receptor in flies. The insulin pathway is a general anabolic pathway, and key regulator of glucose homeostasis. The Nrf2 counters pro-oxidative conditions, also involved in inflammatory responses and metabolism. The Nrf2 fly homolog is Cap’n’collar C (CncC). We quantified glucose, glycogen, and total lipids in control and different pro-oxidative conditions. We corroborated an accumulation of lipids and carbohydrates in the mutants, and document sexual differences. We document also metabolic and survival differences in the responses to “mild” pro-oxidative conditions in young flies (seven days old), with females being most affected. We compare 10 mM paraquat survival of virgin flies to mated mixed-sex flies housed together. We used females to study transcriptomic differences between wild type and <em>S6k</em> hypomorphs. Results highlight dysregulation of lipid and antioxidant enzymes and genes, in agreement with lipid and oxidative metabolism data. Our results are consistent with the insulin/TOR pathway acting as an integrator of intermediate metabolism and oxidative homeostasis (this last together with the CncC pathway).</div></div>","PeriodicalId":12582,"journal":{"name":"General and comparative endocrinology","volume":"362 ","pages":"Article 114672"},"PeriodicalIF":2.1,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143364412","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":"Influence of season, capture method, sample age and extraction protocols on the scale cortisol concentrations of three species of freshwater fish","authors":"Ahmad Ghazal ,&nbsp;Richard Paul ,&nbsp;A. Serhan Tarkan ,&nbsp;J. Robert Britton","doi":"10.1016/j.ygcen.2025.114671","DOIUrl":"10.1016/j.ygcen.2025.114671","url":null,"abstract":"<div><div>Scale cortisol concentration (SCC) is increasingly applied as a biomarker of chronic stress in fish, but knowledge gaps remain on how SCC is affected by the sampling season and method of fish capture, the time since sample collection, and the cortisol extraction protocol. Here, working with three freshwater fishes (common carp <em>Cyprinus carpio</em>, European chub <em>Squalius cephalus</em> and Northern pike <em>Esox lucius</em>), a robust extraction protocol was developed and then applied to identifying how scale cortisol levels can vary in fish populations according to aspects of the fish capture events. Across five scale cortisol extraction protocols, three provided relatively low yields, so their application would result in erroneously low SCC. Application of the extraction protocol providing the highest yields to scale samples indicated that fish sampled in winter have significantly lower SCC than those collected in spring and summer, while fish captured by angling have significantly lower SCC than fish collected from the same population by electric fishing. There were no significant differences in SCC measured from populations across 40 years, suggesting that archived scales potentially provide a valuable resource for measuring temporal changes in SCC. Future studies based on using scale cortisol for analyses of fish chronic stress should consider these issues in their study designs and evaluations to ensure measured differences in cortisol across time and space are due to differences in how the fish are responding to their environment rather than being an artefact of study design.</div></div>","PeriodicalId":12582,"journal":{"name":"General and comparative endocrinology","volume":"362 ","pages":"Article 114671"},"PeriodicalIF":2.1,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143079388","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}