General and comparative endocrinology最新文献

{"title":"Examining the potential decoupling of reproductive-stress interactions in blackbirds with stark differences in reproductive strategy","authors":"Kathleen S. Lynch,&nbsp;Ishveer Kaur","doi":"10.1016/j.ygcen.2026.114979","DOIUrl":"10.1016/j.ygcen.2026.114979","url":null,"abstract":"<div><div>Stress and reproduction are often linked through interactions between the hypothalamic–pituitary–adrenal (HPA) and hypothalamic–pituitary–gonadal (HPG) axes such that stress can suppress reproduction. It is unclear, however, whether species with enhanced annual fecundity exhibit modifications in this interaction. We addressed this question using a comparative study of two closely related blackbird species that differ markedly in parental care and reproductive output: the brown-headed cowbird (<em>Molothrus ater</em>), an obligate brood parasite that has enhanced annual fecundity without parental care, and the red-winged blackbird (<em>Agelaius phoeniceus</em>), which does not have enhanced annual fecundity and provides parental care. We quantified restraint-induced corticosterone and circulating testosterone, 17β-estradiol, and ovarian follicle size in breeding adult females. We also characterized testosterone and corticosterone profiles in nestlings and adults of both species. Corticosterone responses to restraint did not differ between species or age classes but age-related trajectories diverged as corticosterone declined from nestlings to adults in cowbirds but increased in red-winged blackbirds. On the other hand, testosterone concentrations remained stable across species and ages. In adult red-winged blackbirds, reproductive state positively predicted corticosterone responses to restraint, such that individuals with higher testosterone, estradiol, or larger follicles mounted stronger corticosterone responses. In contrast, cowbirds showed no relationship between reproductive state and stress-induced corticosterone. These findings indicate that cowbirds exhibit an altered relationship between reproductive and stress physiology that suggests a functional decoupling between HPA and HPG activity. Such decoupling may support enhanced fecundity in obligate brood parasites.</div></div>","PeriodicalId":12582,"journal":{"name":"General and comparative endocrinology","volume":"383 ","pages":"Article 114979"},"PeriodicalIF":2.1,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148455540","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":"Exploration of Peptide–GPCR Specificity Beyond Homology and Tertiary Structure: Computational Insights into Deorphanization and Molecular mechanisms","authors":"Akira Shiraishi,&nbsp;Honoo Satake","doi":"10.1016/j.ygcen.2026.114980","DOIUrl":"10.1016/j.ygcen.2026.114980","url":null,"abstract":"<div><div>Peptide-responsive G protein-coupled receptors (GPCRs) play pivotal roles in a wide variety of physiological regulatory systems in animals. Despite the substantial expansion of the GPCR and endogenous peptide repertoire identified through large-scale genomic and peptidomic studies, a significant number of receptors remain orphan, particularly those for non-homologous or species-specific peptides. Conventional deorphanization approaches based on sequence or ligand similarity, or receptor structure, are frequently ineffective. These current shortcomings in elucidation of peptide-GPCR interactions result in a persistent gap between sequence information and functional characterization. This review consolidates recent advances in computational approaches that address this challenge by focusing on peptide–GPCR pairs rather than on sequences or structures of peptides and receptors. Pair-centric machine learning frameworks, originally developed in the field of chemical genomics, enable systematic prediction of peptide–GPCR interactions without sequence similarity. Our originally developed machine learning system, PD-incorporated SVM, which incorporates peptide-specific descriptors into the frameworks, has enabled the experimentally validated identification of novel peptide–GPCR pairs in a tunicate and a nematode, and has predicted GPCRs for lineage-specific neuropeptides in ctenophore. In addition to interaction prediction, the present study explores the interaction determinant likelihood (IDL) framework, which offers a mechanistic interpretation of predicted interactions. IDL extracts residue-level determinants of ligand recognition directly from trained models, thereby enabling the identification of peptide features and receptor residues that collectively govern interaction specificity. The application of this approach to closely related GPCR paralogs demonstrates the emergence of distinct peptide specificities through limited, context-dependent residue substitutions, without significant alterations in overall receptor structure. Together, these findings highlight interaction determinants as a unifying framework linking deorphanization, molecular mechanism, and evolutionary diversification of peptide–GPCR signaling.</div></div>","PeriodicalId":12582,"journal":{"name":"General and comparative endocrinology","volume":"383 ","pages":"Article 114980"},"PeriodicalIF":2.1,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148520160","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":"Cathepsins are involved in ovarian remodeling post-parturition in black rockfish (Sebastes schlegelii)","authors":"Jiaqi Liu,&nbsp;Chenpeng Zuo,&nbsp;Xiao Jing,&nbsp;Xuanhan Zhang,&nbsp;Chunxiang Niu,&nbsp;Ming Liu,&nbsp;Mingchun Wu,&nbsp;Chengcheng Zhang,&nbsp;Xin Qi","doi":"10.1016/j.ygcen.2026.114985","DOIUrl":"10.1016/j.ygcen.2026.114985","url":null,"abstract":"<div><div>Cathepsins (CTS) family of lysosomal proteases is characterized by high expression and proteolytic activity across various species. Notably, cathepsin B (CTSB) and cathepsin L (CTSL) have been implicated in uterine remodeling, follicle atrophy, and granulosa cell apoptosis in various vertebrates. This study investigated the role of the CTS members in post-parturitional ovarian remodeling in ovoviviparous black rockfish (<em>Sebastes schlegelii</em>). We cloned the <em>ctsb</em> (993 bp, encoding 330 amino acids) and <em>ctsl</em> (1011 bp, encoding 336 amino acids) genes from black rockfish. Quantitative Real-time PCR (qPCR) analysis revealed widespread tissue distribution for both genes, with <em>ctsb</em> expression being significantly highest in the ovary and markedly upregulated during the parturition process. In contrast, <em>ctsl</em> exhibited low ovarian expression with no increasing trend. In situ hybridization (ISH) and immunohistochemistry (IHC) localized CTSB to the ovarian stromal periphery and specific oocytes. Functional studies using recombinant mature CTSB demonstrated its proteolytic activity on ovarian tissue, leading to a significant increase in arginine (Arg) content. Post-parturition supplementation with Arg notably restored serum nutritional levels. Furthermore, dual- luciferase assays identified functional binding sites for Estrogen Receptor 1 (ESR1) and Specificity Protein 1 (SP1) within the <em>ctsb</em> promoter, regulating its transcription. Collectively, our findings indicate that CTSB, a member of the CTS family, is likely involved in ovarian remodeling in black rockfish.</div></div>","PeriodicalId":12582,"journal":{"name":"General and comparative endocrinology","volume":"383 ","pages":"Article 114985"},"PeriodicalIF":2.1,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148601730","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":"Induction of ovulation in sexually mature zebrafish by injection of gap junction protein CX43 blocker Gap27","authors":"Li Zhou,&nbsp;Feiyan Li,&nbsp;Zhaohan Sun,&nbsp;Kunhuang Han","doi":"10.1016/j.ygcen.2026.114981","DOIUrl":"10.1016/j.ygcen.2026.114981","url":null,"abstract":"<div><div>In aquaculture, ovulation is commonly induced using exogenous hormones, which are associated with broodstock stress, variable responses, and environmental concerns. Gap junctions formed by connexin 43 (Cx43) in ovarian granulosa cells play a critical role in maintaining meiotic arrest by facilitating the transfer of meiosis-inhibiting substances from granulosa cells to oocytes. The present study investigated whether pharmacological blockade of Cx43 using the specific inhibitor Gap27 could induce ovulation in zebrafish as a non-hormonal alternative. Sexually mature female zebrafish were divided into four groups: control (saline), low-dose (50 μM Gap27), medium-dose (150 μM Gap27), and high-dose (250 μM Gap27), with injections administered through the genital pore. Ovulation was assessed at 14 days post-injection by gentle abdominal pressure. The high-dose group achieved an ovulation rate of 77.78% (7/9), whereas no ovulation was observed in the control or low-dose groups, and only one female ovulated in the medium-dose group (11.11%). Histological examination revealed that the high-dose group exhibited loose ovarian tissue with abundant stage V (mature) follicles, while the control and low-dose groups were dominated by stage III and IV follicles. Transcriptomic analysis indicated dose-dependent transcriptional remodeling, with the high-dose group displaying a distinct expression profile. Comparative analysis between the medium-dose and high-dose groups identified 255 differentially expressed genes, from which 17 ovulation-related genes were screened, including <em>mmp9</em>, <em>nos2b</em>, <em>fosb</em>, <em>igf3</em>, <em>nppc</em>, <em>il17ra1a</em>, and <em>plk2b</em>, which are involved in meiotic arrest release, extracellular matrix remodeling, inflammatory signaling, and cell cycle regulation. Based on these findings, a “bypass activation” model is proposed, in which Gap27-mediated blockade of Cx43 triggers four coordinated molecular modules—brake release, inflammation and tissue remodeling, stress and proliferation, and alternative growth signals—ultimately leading to ovulation. Collectively, these results suggest that targeted Cx43 blockade by Gap27 effectively induces ovulation in zebrafish, providing a proof-of-concept for non-hormonal ovulation induction strategies in aquaculture.</div></div>","PeriodicalId":12582,"journal":{"name":"General and comparative endocrinology","volume":"383 ","pages":"Article 114981"},"PeriodicalIF":2.1,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148520204","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":"Explorations in comparative molecular neuroendocrinology: a tribute to Robert M. Dores","authors":"Ciaran A. Shaughnessy,&nbsp;Mathilakath M. Vijayan","doi":"10.1016/j.ygcen.2026.114982","DOIUrl":"10.1016/j.ygcen.2026.114982","url":null,"abstract":"","PeriodicalId":12582,"journal":{"name":"General and comparative endocrinology","volume":"384 ","pages":"Article 114982"},"PeriodicalIF":2.1,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148601782","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":"Modulatory effect of probiotics and Spirulina platensis on the growth performance and immune response of Nile tilapia exposed to sumithion","authors":"Shaharier Ahmed,&nbsp;Esrat Zahan Etti,&nbsp;Md Ruhul Amin,&nbsp;Haphsa Khanom,&nbsp;Shifat Ara Noor,&nbsp;Md Shahjahan,&nbsp;Md. Mahiuddin Zahangir","doi":"10.1016/j.ygcen.2026.114966","DOIUrl":"10.1016/j.ygcen.2026.114966","url":null,"abstract":"<div><div>Pesticide pollution in aquatic ecosystems has been increasing, especially organophosphates such as sumithion, which pose serious risks to non-target aquatic species including Nile tilapia (<em>Oreochromis niloticus</em>). In our study, we systematically assessed the therapeutic effects of probiotics and <em>Spirulina platensis</em> on sumithion-induced oxidative stress, immunosuppression, hematological alterations, and growth inhibition in <em>O. niloticus</em>. A total of 240 fingerlings (12.8 ± 0.09 g) were chosen randomly to receive four treatments for experimentation: control, sumithion (0.30 mg/L), sumithion and probiotics (0.30 mg/L and 1.0 ml/L), and sumithion and <em>Spirulina</em> (0.30 mg/L and 50 g/kg). Each treatment had three repetitions for a duration of six weeks. The exposure of fish to sumithion caused impaired growth performance, significant (<em>p</em> &lt; 0.05) increase in metabolic and oxidative stress markers, as well as a decrease in hemoglobin (Hb) concentration, induced hyperglycemia, and downregulation of immune gene expression. Conversely, treatments with probiotics and <em>Spirulina</em> effectively ameliorated these toxic effects. Probiotics were effective in restoring immune gene expression (interferon-gamma, <em>IFN-γ</em>, interleukin-1 beta, <em>IL-1β</em>; and tumor necrosis factor-alpha, <em>TNF-α</em>), reducing glucose (Glu) levels, and improving growth performance, as evidenced by the highest weight gain, specific growth rate, and increased intestine-somatic index (ISI) and lowest feed conversion ratio. Furthermore, the probiotic-supplemented group showed an upregulation in hepatic <em>igf-1</em>, <em>igf-2</em> (insulin-like growth factors) and pituitary <em>gh</em> (growth hormone) expression levels. In contrast, <em>Spirulina</em> had a greater impact on promoting antioxidant activity and boosting hematological parameters, particularly by improving Hb, <em>SOD</em> (superoxide dismutase), and <em>CAT</em> (catalase) levels, while also contributing to a significant increase in hepatosomatic index (HSI). These results emphasize the effectiveness of probiotics and <em>Spirulina</em> as eco-friendly complements to alleviate sumithion-prevailed toxicity, enhancing growth, immune response, and antioxidant capacity in <em>O. niloticus</em>, with probiotics being an effective approach in easing physiological impairments.</div></div>","PeriodicalId":12582,"journal":{"name":"General and comparative endocrinology","volume":"383 ","pages":"Article 114966"},"PeriodicalIF":2.1,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148375360","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":"A novel culture method for Rana [Lithobates] catesbeiana olfactory epithelium reveals differential effects of transcriptional and translational inhibitors on the temperature-dependent induction of thyroid hormone-responsive transcripts","authors":"Emma M. Field,&nbsp;Caren C. Helbing","doi":"10.1016/j.ygcen.2026.114988","DOIUrl":"10.1016/j.ygcen.2026.114988","url":null,"abstract":"<div><div>Amphibian organ culture is invaluable for gaining insight into thyroid hormone (TH) action. The olfactory epithelium (OE) of <em>Rana (aka Aquarana or Lithobates) catesbeiana</em> tadpoles is a highly TH-sensitive tissue that regulates essential survival behaviors and undergoes drastic remodeling during TH-dependent metamorphosis. These features make it a valuable bioindicator for normal and disrupted TH action. To our knowledge, we developed and validated the first successful <em>ex vivo</em> culture method for anuran tadpole olfactory epithelium. Pairs of OE-containing principal cavities from premetamorphic tadpoles were excised, each cavity cut in half, and exposed to 10 nM 3,5,3′-triiodothyronine (T₃) or solvent control at 24 °C for 24 h. Each half cavity showed consistent enrichment of the olfactory marker <em>omp</em> compared to back skin. Robust and reproducible TH responses were observed in individual, unpooled cultured olfactory epithelium (C-OE) as measured by reverse transcription-quantitative polymerase chain reaction of TH-responsive transcripts <em>thra</em>, <em>thrb</em>, and <em>thibz</em>. No spatial variation in hormone sensitivity within the principal cavity was observed supporting the use of repeated-measures statistics while capturing biological variation between animals. To probe early TH signaling events, C-OE and cultured back skin (C-skin) were treated with T₃ in the presence of transcriptional and translational inhibitors at 24 °C or 4 °C. The cold condition represents a metamorphic stasis period during which the TH signal is initiated, but metamorphosis does not proceed. Notably, TH-induction of <em>thibz</em> at 4 °C was unaffected by transcriptional inhibition in both tissues, suggesting that mechanisms other than RNA synthesis may be driving the increase in transcript abundance.</div></div>","PeriodicalId":12582,"journal":{"name":"General and comparative endocrinology","volume":"384 ","pages":"Article 114988"},"PeriodicalIF":2.1,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148683681","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":"The sole Drosophila melanogaster insulin receptor gene mediates metabolism and movement regulating lipid and carbohydrate stores, sleep, and motor activity","authors":"Jéssica Paloma Álvarez-Rendón,&nbsp;Juan Rafael Riesgo-Escovar","doi":"10.1016/j.ygcen.2026.114984","DOIUrl":"10.1016/j.ygcen.2026.114984","url":null,"abstract":"<div><div>The insulin signaling pathway is a core and evolutionarily conserved signal transduction network. Here we study hypomorphic mutant conditions in the sole insulin receptor gene (<em>Inr</em>) in the fruit fly <em>Drosophila melanogaster</em>, placed at the beginning of the signaling cascade where it mediates the effects from the seven <em>Drosophila</em> insulin-like peptides. As such, it sits at a nodal point where signaling must pass to ensure and carry out all the functions ascribed to this anabolic pathway. We find that these mutant flies, while viable, exhibit hyperactivity and accumulate glycogen and body lipids. The hyperactivity phenotype was characterized in detail and is significantly different from controls both measuring it in several days' spells, or when done in a more detailed fashion in shorter time periods (twenty-five minutes). The proportion of time spent sleeping is also altered, highlighting the robust role that the insulin pathway has not only regulating metabolism but also behavior. When confronted with mild pro-oxidative conditions, these flies and control wildtype flies have reduced lifespans as well. The metabolic dysregulation is rescued when the <em>Inr</em> mutant flies are also heterozygous for <em>keap1</em>, a negative regulator of the <em>Nrf2</em> pathway, while the antioxidant response and the activity/sleep levels exhibit only partial and sexually dimorphic improvements. Transcriptomic analyses of <em>Inr</em> mutants show that many metabolism and hormonal signaling genes are dysregulated.</div></div>","PeriodicalId":12582,"journal":{"name":"General and comparative endocrinology","volume":"384 ","pages":"Article 114984"},"PeriodicalIF":2.1,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148684268","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":"Comparative analysis of the expression and localization of prolactin 1A and 1B in the pituitary gland of the red-bellied newt Cynops pyrrhogaster","authors":"Takatoshi Ikeda,&nbsp;Yuriko Sudo,&nbsp;Momoka Itao,&nbsp;Yousuke Tsuneoka,&nbsp;Masahiro Matsuno,&nbsp;Shawichi Iwamuro,&nbsp;Reiko Okada,&nbsp;Sakae Kikuyama,&nbsp;Itaru Hasunuma","doi":"10.1016/j.ygcen.2026.114978","DOIUrl":"10.1016/j.ygcen.2026.114978","url":null,"abstract":"<div><div>The authentic prolactin (PRL) designated PRL1 is a multifunctional hormone secreted by the anterior pituitary gland of vertebrates. The PRL1 gene exists in two forms: fish-type PRL1 gene (<em>PRL1B</em>) and tetrapod-type PRL1 gene (<em>PRL1A</em>). It has been proposed that <em>PRL1B</em> gene underwent duplication during the early amphibian lineage. Subsequently, the ancestral gene (<em>PRL1B</em>) was lost in amniotes, while the newly duplicated gene (<em>PRL1A</em>) was retained. Notably, only amphibians possess both <em>PRL1B</em> and <em>PRL1A</em> genes. In the anuran amphibian bullfrog, <em>PRL1A</em> gene expression is low during the pre- and prometamorphic stages, gradually increasing toward the end of the metamorphic climax stage. In contrast, <em>PRL1B</em> gene expression is relatively high during the early metamorphic stages but significantly declines during the metamorphic climax stage and becomes undetectable after completion of metamorphosis. These differential expression patterns suggest a functional transition of PRL1 paralogs associated with the shift from aquatic to terrestrial life. However, data on <em>PRL1B</em> expression in urodele amphibians remain limited. In this study, we cloned the <em>PRL1B</em> cDNA from the urodele amphibian, the red-bellied newt (<em>Cynops pyrrhogaster</em>) and analyzed its expression in the pituitary gland. Unlike in anuran bullfrog, PRL1B is expressed as the transcript and protein in the adult pituitary of this urodele species, suggesting that the regulatory mechanism controlling <em>PRL1B</em> expression in urodeles differs from that in anurans. This is the first report demonstrating the existence of PRL1B in urodeles in the form of protein as well as mRNA.</div></div>","PeriodicalId":12582,"journal":{"name":"General and comparative endocrinology","volume":"383 ","pages":"Article 114978"},"PeriodicalIF":2.1,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148445666","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":"Assessing staining methods for amphibian sperm viability and morphological assessment: several different methods are acceptable to assess amphibian sperm quality","authors":"Shannon Murphy,&nbsp;Nina Ross,&nbsp;Natalie Tear,&nbsp;Claudia Hui Wen Khoo,&nbsp;Daniel Vivas Barreto,&nbsp;Dilakni D. Udapitya,&nbsp;Laura A. Brannelly","doi":"10.1016/j.ygcen.2026.114983","DOIUrl":"10.1016/j.ygcen.2026.114983","url":null,"abstract":"<div><div>Assisted reproduction methodologies are essential to protect species from extinction. But to improve reproductive outcomes, we need to understand gamete quality. Gamete quality assays are powerful functional endpoints for comparative endocrinology, especially when they are integrated with hormone measurements and experimental manipulations. However, the methodologies for assessing amphibian gamete quality do not have published validation or comparisons within the literature. In this study we analysed sperm samples from two bell frog species, looking at morphology (measuring sperm head and sperm tail length) using both wet mounts and dry mounts of three different stains (unstained mounts, Coomassie blue and eosin nigrosin). We also assessed viability in the same sperm samples using three different preparations (eosin nigrosin dry mount, eosin nigrosin wet mount, and fluorescent SYBR-14 propidium iodide). We found that the methods varied in mean morphological measurements. For example, sperm tail lengths were measured longer when the slides were dry mounts, and when the eosin nigrosin stain was used. There were differences among species as well, where, for example, stain type influenced the sperm head length in one species, but not in the other species. Importantly, all methods had similar variance, indicating that all staining techniques are suitable given that the methods used are consistent within a study. For viability assessment, the dried eosin nigrosin staining method showed lower viability, while the wet mount of eosin nigrosin and the fluorescent SYBR-14 propidium iodide stain were statistically equivalent. These results indicate that there are a wide range of methodologies that can be used for sperm quality assessment of amphibian sperm, and researchers must choose the methodology best suited for the study.</div></div>","PeriodicalId":12582,"journal":{"name":"General and comparative endocrinology","volume":"384 ","pages":"Article 114983"},"PeriodicalIF":2.1,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148591223","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}