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24 pages, 8647 KB  
Article
Mechanical Insights into the Distinct Effects of Ovariectomy Versus Adrenalectomy on Age-Related Thymic Atrophy in Female Mice
by Junan Chen, Xudong Zhou, Ling Wei, Zixuan Tian, Haozhe Zeng, Fei Yan, Junhua Zhou, Xianyin Zeng, Fengyan Meng, Xiaohan Cao, Haozhou Li and Xingfa Han
Int. J. Mol. Sci. 2026, 27(2), 1022; https://doi.org/10.3390/ijms27021022 - 20 Jan 2026
Abstract
Age-related thymic atrophy, a hallmark of immunosenescence linked to age-related diseases, involves gonadal and adrenal steroid hormones, but their distinct roles and mechanisms in this process remain unclear. Through biochemical, histological, and RNA-seq analyses, we comprehensively explored the mechanisms underpinning age-related thymic atrophy [...] Read more.
Age-related thymic atrophy, a hallmark of immunosenescence linked to age-related diseases, involves gonadal and adrenal steroid hormones, but their distinct roles and mechanisms in this process remain unclear. Through biochemical, histological, and RNA-seq analyses, we comprehensively explored the mechanisms underpinning age-related thymic atrophy in response to ovariectomy (OVX) versus adrenalectomy (ADX) in female mice. Compared to the sham controls, OVX overtly ameliorated age-related thymic atrophy, as evidenced by increased thymus mass, a larger gross thymus area, and denser cortex cellularity. In contrast, ADX evidently accelerated age-related thymic atrophy, characterized by increased adipose infiltration and decreased cortex/medulla ratio, obscure cortico-medullary junctions, and sparser thymic cortical cells. Unexpectedly, combined OVX and ADX displayed a more pronounced effect than OVX alone in ameliorating age-related thymic atrophy. Mechanistically, OVX decreased while ADX increased the circulating 17β-estradiol levels in female mice, which drove these opposing outcomes potentially by promoting Pparg-mediated thymic fat deposition and blocking Cdk1-dependent thymocyte cell cycle progression. Although OVX eliminated gonadal 17β-estradiol production, it appeared to trigger a compensatory adrenal-dependent estrogen biosynthesis, whereas combined OVX and ADX nearly eliminated all estrogen sources, thus leading to a more pronounced effect than OVX alone in ameliorating age-related thymic atrophy in female mice. Notably, OVX increased while ADX decreased serum corticosterone levels, but these alterations exerted minimal impacts on age-related thymic atrophy, highlighting a pivotal role of estrogens over glucocorticoids in accelerating age-related thymic atrophy in females. Undesirably, although OVX ameliorated age-related thymic atrophy, it appeared to simultaneously increase autoimmune susceptibility by downregulating thymic Cd74 expression. Taken together, our results indicate that OVX ameliorates while ADX accelerates age-related thymic atrophy in females. Estrogens rather than glucocorticoids act as the predominant regulator of this process, potentially via promoting Pparg-dependent fat deposition and blocking Cdk1-dependent thymocyte cycle progression. However, OVX-induced estrogen depletion also elevated autoimmune risk, emphasizing the need to balance benefits and risks in regulating thymic aging. Full article
(This article belongs to the Section Molecular Endocrinology and Metabolism)
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12 pages, 548 KB  
Article
17β-Estradiol Does Not Designate Non-Sex-Specific Early Ventricular Arrhythmia in Acute Myocardial Infarction, in Contrast to C-Reactive Protein
by Niya E. Semedzhieva, Adelina Tsakova, Vesela Lozanova, Petar I. Atanasov and Dobrinka Dineva
Int. J. Mol. Sci. 2026, 27(2), 970; https://doi.org/10.3390/ijms27020970 - 19 Jan 2026
Abstract
Despite the evidence from experimental studies that endogenous hormones have sex-related effects on action potential duration, the relationship between gonadal steroids and ventricular repolarization in acute myocardial infarction (AMI) is not clear. We tested the hypothesis that endogenous 17β-estradiol (E2) and 17β-estradiol-to-testosterone ratio [...] Read more.
Despite the evidence from experimental studies that endogenous hormones have sex-related effects on action potential duration, the relationship between gonadal steroids and ventricular repolarization in acute myocardial infarction (AMI) is not clear. We tested the hypothesis that endogenous 17β-estradiol (E2) and 17β-estradiol-to-testosterone ratio (E2/T) are associated with inflammation, influencing the occurrence of early ventricular arrhythmia (VA) in AMI. Electrocardiographic (ECG) repolarization indices, including resting heart rate (HR), corrected QT (QTc) interval, QTc minimum (QTcmin), QTc maximum (QTcmax), and QTc dispersion (QTcd), along with E2, total T, and the ratio of E2 to T (E2/T), were measured and analyzed after percutaneous coronary intervention in 86 patients (36 women, 41.9%). In a non-specific sex analysis, the incidence of early VA in the course of AMI was determined by the ejection fraction of the left ventricle (OR 0.876, p = 0.054), and by the peak levels of plasma C-reactive protein (OR 1.026, p = 0.077). Endogenous plasma 17β-estradiol tended to be higher in cases with early ventricular arrhythmia (124.5 ± 79 vs. 181 ± 192.8, p = 0.089). 17β-estradiol levels were significantly predicted by C-reactive protein (OR 1.050, p = 0.042). This study found that reduced systolic function of the left ventricle and higher peak CRP levels are associated with endogenous plasma 17β-estradiol in the acute phase of MI, and predicted the risk of early in-hospital ventricular arrhythmia. Full article
(This article belongs to the Special Issue Steroids in Human Disease and Health)
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18 pages, 3335 KB  
Article
Heavy Metal Bioaccumulation in European Eels (Anguilla anguilla) from the Odra and Vistula River Basins (Poland): Implications for Environmental and Food Safety
by Joanna Nowosad, Tomasz K. Czarkowski, Andrzej Kapusta, Natalia Mariańska, Piotr Chmieliński, Bartosz Czarnecki, Jakub Pyka, Michał K. Łuczyński, Gulmira Ablaisanova and Dariusz Kucharczyk
Animals 2026, 16(2), 287; https://doi.org/10.3390/ani16020287 - 16 Jan 2026
Viewed by 86
Abstract
The accumulation of heavy metals in fish tissues is widely recognized as an indicator of aquatic environmental pollution, and the analysis of their content provides a basis for assessing ecological risk and the safety of aquatic food. The European eel (Anguilla anguilla [...] Read more.
The accumulation of heavy metals in fish tissues is widely recognized as an indicator of aquatic environmental pollution, and the analysis of their content provides a basis for assessing ecological risk and the safety of aquatic food. The European eel (Anguilla anguilla) is a species frequently used as a bioindicator in environmental studies due to its wide geographic distribution, long life cycle, and high capacity for bioaccumulation of heavy metals in various tissues. The aim of this study was to assess the variation in the accumulation of heavy metals, i.e., mercury (Hg), lead (Pb), arsenic (As), and cadmium (Cd), in the tissues (muscle, liver, gonads, and gills) of European eels caught in two locations in Polish inland waters. The obtained results showed significant differences both in the concentration levels of individual elements and in their co-occurrence in the examined tissues. The statistical methods used, including correlation analysis, heat maps, and principal component analysis (PCA), allowed for a comprehensive assessment of the relationships between metals and the identification of factors differentiating the studied populations. The obtained results clearly indicate that fish residing in similar environments for long periods exhibit significant differences in heavy metal content in various fish tissues. Fish obtained from environments with potentially higher levels of heavy metal inputs, such as the Oder River EMU compared with the Vistula River EMU, showed higher levels of heavy metal accumulation in tissues. This study also found that the concentration of heavy metals tested did not exceed the safe standards for human fish consumption. Full article
(This article belongs to the Section Aquatic Animals)
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14 pages, 1179 KB  
Review
Gonadotropins in Mini-Puberty: Pathophysiological and Therapeutic Implications for Male Congenital Hypogonadism
by Ignazio Cammisa, Donato Rigante and Clelia Cipolla
Children 2026, 13(1), 133; https://doi.org/10.3390/children13010133 - 15 Jan 2026
Viewed by 165
Abstract
Background: Mini-puberty is a transient but critical postnatal activation of the hypothalamic–pituitary–gonadal axis, essential for male gonadal maturation, penile and testicular growth, and future reproductive potential: this physiological hormonal surge is absent or blunted in congenital hypogonadotropic hypogonadism (CHH), often manifesting as micropenis, [...] Read more.
Background: Mini-puberty is a transient but critical postnatal activation of the hypothalamic–pituitary–gonadal axis, essential for male gonadal maturation, penile and testicular growth, and future reproductive potential: this physiological hormonal surge is absent or blunted in congenital hypogonadotropic hypogonadism (CHH), often manifesting as micropenis, cryptorchidism, and impaired Sertoli cell proliferation. Objective: The aim of this review is to summarize current evidence on the impact of early gonadotropin therapy in male infants with CHH. Methods: We conducted a comprehensive literature review using PubMed, including studies reporting on male infants with confirmed or suspected CHH receiving gonadotropin therapy. Keywords included “mini-puberty and hypogonadism”, “gonadotropins and infancy,” and “gonadotropin therapy in CHH.” Eligible studies reported biochemical outcomes (luteinizing hormone, follicle-stimulating hormone, testosterone, inhibin B, anti-Müllerian hormone) and clinical measures (penile length, testicular volume, testicular descent). Data extraction focused on endocrine responses, genital growth, and safety. Results: Twelve studies including 95 infants were analyzed. Early gonadotropin therapy effectively restored postnatal hormonal levels, with consistent increases in testosterone, inhibin B, and anti-Müllerian hormone. Clinically, treatment induced significant penile growth, increased testicular volume and partial or complete testicular descent in the majority of cases. Both continuous infusion and intermittent injection regimens were effective, though hormone kinetics and growth responses varied. No serious adverse events were reported, and therapy was generally well tolerated. Conclusions: Early gonadotropin therapy during mini-puberty represents a safe and effective intervention to replicate the physiological postnatal hormonal surge in male infants with CHH. Prospective longitudinal studies are warranted to evaluate sustained effects on puberty, fertility, and adult reproductive function. Full article
(This article belongs to the Section Pediatric Endocrinology & Diabetes)
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15 pages, 1289 KB  
Article
Oxidative Stress Biomarkers in Carassius gibelio from Lakes of Varying Ecological Quality
by Dimitra Petrocheilou, Olga Petriki, Martha Kaloyianni and Dimitra C. Bobori
Hydrobiology 2026, 5(1), 4; https://doi.org/10.3390/hydrobiology5010004 - 14 Jan 2026
Viewed by 79
Abstract
The Water Framework Directive 2000/60/EC requires the assessment of the ecological quality in all surface waters using biological indices, yet the effective application of these indices often demands extensive and long-term monitoring data. Oxidative stress biomarkers offer a promising complementary approach, as they [...] Read more.
The Water Framework Directive 2000/60/EC requires the assessment of the ecological quality in all surface waters using biological indices, yet the effective application of these indices often demands extensive and long-term monitoring data. Oxidative stress biomarkers offer a promising complementary approach, as they can detect early biochemical responses of organisms to environmental degradation. In this study, we evaluated the suitability of two oxidative stress biomarkers—malondialdehyde (MDA) levels and DNA damage—in the gonads of a freshwater fish species, the Prussian carp Carassius gibelio (Bloch, 1782) as indicators of ecological condition in lakes of differing environmental quality. Fish were sampled from four lakes (Doirani, Vegoritida, Volvi, Petron; Northern Greece) representing a gradient of physicochemical and ecological quality. Both MDA concentrations and DNA damage showed significant (p < 0.05) differences among lakes. However, only DNA damage in the gonads was significantly (p < 0.05) associated with lake ecological quality as determined by the Greek Lake Fish Index (GLFI), with higher biomarker responses observed in lakes of poorer status. These findings demonstrate that oxidative stress biomarkers in C. gibelio reflect variations in lake ecological quality and may serve as sensitive, early-warning tools for biomonitoring and pollution assessment in freshwater ecosystems. Full article
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14 pages, 2704 KB  
Case Report
46,XY DSD with Partial Gonadal Dysgenesis and Growth Failure in a Patient with 3q27.1 Microdeletion: Candidate Gene Curation After Exhaustive Literature Review
by Lourdes Correa Brito, Sofía Suco, Bárbara Casali, Florencia Villegas, Paula Scaglia, Agustín Izquierdo, Jimena Lopez Dacal, Miguel Podestá, Martín Medin, Romina P. Grinspon, María Gabriela Ropelato and Rodolfo A. Rey
Int. J. Mol. Sci. 2026, 27(2), 821; https://doi.org/10.3390/ijms27020821 - 14 Jan 2026
Viewed by 108
Abstract
Complex genetic syndromes represent a diagnostic challenge due to their diverse phenotypic presentations, which often evolve over time and may not be fully evident at birth. Disorders of sex development (DSD) comprise congenital conditions with discordance between chromosomal, gonadal, and/or genital sex. In [...] Read more.
Complex genetic syndromes represent a diagnostic challenge due to their diverse phenotypic presentations, which often evolve over time and may not be fully evident at birth. Disorders of sex development (DSD) comprise congenital conditions with discordance between chromosomal, gonadal, and/or genital sex. In 46,XY gonadal dysgenesis, undervirilisation or female-appearing genitalia may occur despite a normal karyotype, and diagnosis increasingly relies on genomic approaches. Prenatal and postnatal growth failure has been described in patients with syndromic 46,XY DSD. We report a male patient with SGA, lack of postnatal catch-up growth, and syndromic dysgenetic 46,XY DSD followed longitudinally from infancy to 11 years, in whom whole-exome sequencing (WES) reanalysis revealed a pathogenic 2.7 Mb microdeletion at 3q27.1q27.2. Systematic review of previously reported 3q27.1 deletions identified overlapping phenotypes but limited documentation of gonadal dysfunction. Curation of 71 genes within the deleted region highlighted DVL3 and CLCN2 as potential contributors to the gonadal phenotype, although functional evidence remains lacking. This case expands the phenotypic spectrum of 3q27.1 microdeletion syndrome, suggesting that 46,XY gonadal dysgenesis may represent an under-recognised feature. It also underscores the importance of copy number variant (CNV) analysis and periodic re-evaluation of sequencing data to increase diagnostic yield. Full article
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19 pages, 774 KB  
Review
The Global Burden of Obstructive Sleep Apnea on Fertility: Pathophysiology, Clinical Evidence, and Therapeutic Perspectives
by Matteo Lazzeroni, Mario Lentini, Antonella Maruca, Pasquale Capaccio, Jerome Rene Lechien, Basilio Pecorino, Benito Chiofalo, Giuseppe Scibilia, Salvatore Maira, Paolo Scollo and Antonino Maniaci
Reprod. Med. 2026, 7(1), 4; https://doi.org/10.3390/reprodmed7010004 - 12 Jan 2026
Viewed by 152
Abstract
Obstructive sleep apnea (OSA) is a highly prevalent disorder with far-reaching systemic consequences. While its cardiometabolic and neurocognitive impacts are well established, growing evidence highlights OSA as a contributor to infertility in both men and women. The pathophysiological mechanisms include intermittent hypoxia, oxidative [...] Read more.
Obstructive sleep apnea (OSA) is a highly prevalent disorder with far-reaching systemic consequences. While its cardiometabolic and neurocognitive impacts are well established, growing evidence highlights OSA as a contributor to infertility in both men and women. The pathophysiological mechanisms include intermittent hypoxia, oxidative stress, systemic inflammation, and endocrine disruption, all of which can impair spermatogenesis, reduce semen quality, alter gonadal hormone secretion, and compromise ovarian function. Clinical studies consistently demonstrate associations between OSA and impaired semen parameters, reduced testosterone, and erectile dysfunction in men. In women, OSA is frequently observed in those with polycystic ovary syndrome, is associated with ovulatory dysfunction, and negatively affects in vitro fertilization outcomes, pregnancy rates, and miscarriage risk. Despite these findings, infertility is not systematically included in global burden estimates of OSA, leading to the underestimation of its true health and socioeconomic impact. Therapeutic strategies such as weight loss, continuous positive airway pressure, and integrative approaches show promise, though robust evidence from randomized trials is still lacking. Integrating sleep health into reproductive medicine may provide a cost-effective and equitable pathway to improve fertility outcomes worldwide. Full article
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61 pages, 2889 KB  
Review
Understanding the Secular Decline in Testosterone: Mechanisms, Consequences, and Clinical Perspectives
by Óscar Fraile-Martínez, Miguel A. Ortega and Cielo García-Montero
Int. J. Mol. Sci. 2026, 27(2), 692; https://doi.org/10.3390/ijms27020692 - 9 Jan 2026
Viewed by 299
Abstract
Testosterone is a key regulator of male and female physiology, influencing reproductive function, muscle and bone anabolism, metabolic homeostasis, and psychological well-being. Growing evidence indicates a secular, age-independent decline in testosterone levels across populations, a trend associated with reduced fertility, metabolic and cardiovascular [...] Read more.
Testosterone is a key regulator of male and female physiology, influencing reproductive function, muscle and bone anabolism, metabolic homeostasis, and psychological well-being. Growing evidence indicates a secular, age-independent decline in testosterone levels across populations, a trend associated with reduced fertility, metabolic and cardiovascular dysfunction, mood disturbances, and impaired quality of life. While aging and genetic factors play a role, a wide range of modifiable influences—including obesity, physical inactivity, unhealthy dietary patterns, chronic stress, poor sleep, and exposure to endocrine-disrupting chemicals or other environmental stressors—appear to contribute substantially to this phenomenon. This narrative review synthesizes the evidence on testosterone’s physiological significance, the causes and consequences of its secular decline, and evaluates potential interventions, emphasizing lifestyle and environmental strategies (physical activity, nutrition, weight management, sleep, stress reduction, sunlight exposure) as well as pharmacological and nutraceutical options. Overall, the contemporary testosterone decline represents a complex, multifactorial public health issue requiring integrated approaches to preserve hormonal and systemic health. Full article
(This article belongs to the Special Issue Molecular Research on Reproductive Physiology and Endocrinology)
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20 pages, 3383 KB  
Article
Gonadal Transcriptome Analysis Identifies Sex-Related Genes and Regulatory Pathways in Spotted Longbarbel Catfish (Hemibagrus guttatus)
by Kun Zhao, Yuanyuan Wang, Yexin Yang, Yi Liu, Chao Liu, Shandian Zhu, Jinhui Sun and Xidong Mu
Fishes 2026, 11(1), 43; https://doi.org/10.3390/fishes11010043 - 9 Jan 2026
Viewed by 230
Abstract
Hemibagrus guttatus is a large omnivorous fish of significant economic value, listed as a Class II protected species in the National Key Protected Wildlife List in 2021 in China. To provide a theoretical foundation for the artificial breeding of H. guttatus, this [...] Read more.
Hemibagrus guttatus is a large omnivorous fish of significant economic value, listed as a Class II protected species in the National Key Protected Wildlife List in 2021 in China. To provide a theoretical foundation for the artificial breeding of H. guttatus, this study employs high-throughput transcriptome sequencing of testes and ovaries to elucidate the molecular regulatory pathways involved in sex differentiation. Because H. guttatus exhibits no obvious sexual dimorphism even during the breeding season, the distinctive contribution of this study compared with previous gonadal-transcriptomic investigations in other Siluriformes lies not only in documenting sex-biased genes but also in providing a molecular foundation for developing non-lethal sex-identification methods for this morphologically indistinguishable species. A total of 303,192,896 raw reads were obtained, with an effective data rate of 98.4%, indicating high sequencing quality. Differential expression analysis identified 8694 genes, including 6369 upregulated in testes and 2325 upregulated in ovaries. Among these, 88 genes were functionally annotated as sex-related, with 62 testis-biased genes such as spata17, sox9, and dmrt1, and 26 ovary-biased genes including cyp19a, wnt8, and sox12. KEGG pathway enrichment analysis revealed that the TGF-β signaling pathway, insulin secretion, and steroid hormone biosynthesis may play crucial roles in gonadal development and differentiation in H. guttatus. The expression patterns of key genes such as hsd11b1, amh, and insl3 were validated by quantitative real-time PCR, showing consistency with the transcriptome results. These findings lay a molecular foundation for understanding the regulatory mechanisms of sex differentiation in H. guttatus, and provide candidate genes for further investigation into the genetic basis of gonadal development, which is essential for improving artificial reproduction and selective breeding practices. Full article
(This article belongs to the Special Issue Germplasm Resources and Genetic Breeding of Aquatic Animals)
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15 pages, 2719 KB  
Article
KBN2202 Suppresses Gonadal White Adipose Tissue Expansion in Female Mice Fed a High-Fat Diet
by Moonhang Kim, Jeong-Hyeon Heo, Seok Hwan Chang, Sun-Young Lee, Jihun Kim, Moon-Geun Shin, Jong Sung Kim, Mi Ran Choi and Sang-Rae Lee
Int. J. Mol. Sci. 2026, 27(2), 627; https://doi.org/10.3390/ijms27020627 - 8 Jan 2026
Viewed by 142
Abstract
Obesity treatments increasingly target multiple pathways beyond appetite suppression. We evaluated KBN2202, a salicylate-derived small molecule, in a high-fat diet (60% kcal from fat) mouse model using female and male C57BL/6J mice treated for 8 weeks with oral KBN2202 (20 mg/kg/day) or a [...] Read more.
Obesity treatments increasingly target multiple pathways beyond appetite suppression. We evaluated KBN2202, a salicylate-derived small molecule, in a high-fat diet (60% kcal from fat) mouse model using female and male C57BL/6J mice treated for 8 weeks with oral KBN2202 (20 mg/kg/day) or a matched-volume vehicle (1% DMSO/PBS). Body weight was recorded weekly, and food intake was measured daily; serum hormones and cytokines, adipose tissue histology, and open-field behavior were assessed at the end of the study. Under our experimental conditions, HFD increased body weight and gonadal white adipose tissue (gWAT)/brown adipose tissue (BAT) mass in females, whereas males showed only modest HFD-associated weight gain and did not develop a clear obesity phenotype. KBN2202 significantly reduced peri-ovarian gWAT mass and adipocyte size without altering overall body weight. In females, circulating glucagon-like peptide-1 (GLP-1) increased, uncoupling protein 1 (UCP1) in gWAT showed a non-significant upward trend, and serum TNF-α was selectively decreased, while MCP-1 and IL-1β were unchanged. Locomotor activity was unaltered, and anxiety-like behavior was reduced. Male mice did not show comparable adipose effects. These findings indicate depot-specific, peripheral modulation of adipose remodeling, hormonal balance, and inflammatory tone by KBN2202, supporting its further investigation as an adipose-targeted metabolic modulator complementary to incretin-based therapies. Full article
(This article belongs to the Section Molecular Endocrinology and Metabolism)
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16 pages, 2482 KB  
Article
Dietary Glyphosate Exposure Disrupts Hepatic and Reproductive Function in Female Zebrafish at Regulatory Safe Levels
by Christian Giommi, Marta Lombó, Francesca Maradonna, Gabriella Pinto, Fiorenza Sella, Carolina Fontanarosa, Hamid R. Habibi, Angela Amoresano and Oliana Carnevali
Toxics 2026, 14(1), 59; https://doi.org/10.3390/toxics14010059 - 7 Jan 2026
Viewed by 468
Abstract
Glyphosate (GLY), the active ingredient in widely used herbicides, was long considered specific to plants and bacteria, yet mounting evidence shows it can impair endocrine and reproductive functions in animals. Given its widespread use and environmental persistence, assessing its effects at regulatory-approved doses [...] Read more.
Glyphosate (GLY), the active ingredient in widely used herbicides, was long considered specific to plants and bacteria, yet mounting evidence shows it can impair endocrine and reproductive functions in animals. Given its widespread use and environmental persistence, assessing its effects at regulatory-approved doses is critical. Here, adult female zebrafish (Danio rerio) were exposed for 21 days to different concentrations of dietary GLY at 0.5 mg/kg body weight/day (GLY0.5, acceptable daily intake, ADI), 5 mg/kg/day (GLY5), and 50 mg/kg/day (GLY50, no-observed-adverse-effect level, NOAEL). Our findings show that dietary GLY induces dose-dependent perturbations along the hepato-gonadal axis. At the highest dose, chronic stress responses were evident through elevated cortisol and cortisone, accompanied by hepatic glycogen accumulation and ferroptotic stress. Although follicle histology appeared normal, alterations in several genes involved in oocyte maturation and estrogen receptor signaling translated into reduced fertilization, revealing compromised gamete quality rather than overt follicular development abnormality. Likewise, the lowest dose triggered modifications in genes crucial for oogenesis without altering the follicle development, although in this case, potential compensatory mechanisms could have led to enhanced fertilization. GLY5 did not alter the number of fertilized eggs but significantly increased embryo mortality. Overall, dietary GLY disrupted hepatic metabolism, endocrine signaling, and reproduction in a non-monotonic manner, even at levels considered safe by EFSA. These findings highlight the need to reevaluate current safety thresholds with attention to female-specific reproductive risks. Full article
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15 pages, 3280 KB  
Article
Identification and Functional Analysis of tgfb2b Gene in Ovarian Development of Chinese Tongue Sole (Cynoglossus semilaevis)
by Xihong Li, Kaili Zhang, Yue Zhang, Zhijie Li, Zhangfan Chen, Hongyan Wang, Songlin Chen and Na Wang
Biomolecules 2026, 16(1), 105; https://doi.org/10.3390/biom16010105 - 7 Jan 2026
Viewed by 328
Abstract
Transforming growth factor β (TGF-β) superfamily members are critical in teleost sex determination and differentiation. Tgfb2b is an important TGF-β ligand gene exhibiting dominant expression in the ovary of Chinese tongue sole (Cynoglossus semilaevis), yet its function in sex regulation remains [...] Read more.
Transforming growth factor β (TGF-β) superfamily members are critical in teleost sex determination and differentiation. Tgfb2b is an important TGF-β ligand gene exhibiting dominant expression in the ovary of Chinese tongue sole (Cynoglossus semilaevis), yet its function in sex regulation remains unclear. In the present study, the gene expression pattern, transcriptional regulation, and knockdown effect were examined. Its expression persisted and showed a gradual increase throughout ovarian development from 3 months to 1.5 years post-hatching. In situ hybridization (ISH) revealed that the gene was distributed across oocytes at stages I–III, while scarcely detectable in the testis. The transcriptional factors CCAAT/enhancer binding protein α (C/EBPα) and Jun proto-oncogene AP-1 transcription factor subunit (c-Jun) could repress the activity of tgfb2b promoter. In vitro knockdown of tgfb2b in C. semilaevis ovarian cells led to downregulation of its downstream genes (e.g., smad1 and smad2) as well as other sex-related genes (e.g., foxl2 and esr2b). Moreover, multi-omics analysis indicated that, in C. semilaevis gonads, a miRNA named novel-m0083-3p showed an opposite expression pattern with tgfb2b and might have a binding site with the gene. By dual-luciferase assay, tgfb2b was validated to be directly targeted and suppressed by the miRNA. These results demonstrate that tgfb2b plays a significant role in ovarian differentiation and development. Further functional and molecular studies on the interplay between tgfb2b and the foxl2–cyp19a–esr axis will help elucidate the regulatory network underlying sex development in teleost. Full article
(This article belongs to the Section Molecular Genetics)
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21 pages, 5377 KB  
Article
Comparative RNA-Seq Analysis of Differentially Expressed Genes in the Testis and Ovary of Mudskipper, Boleophthalmus pectinirostris
by He Ma, Chao Bian, Changxu Tian, Hongjuan Shi, Tianli Wu, Siping Deng, Guangli Li and Dongneng Jiang
Animals 2026, 16(1), 150; https://doi.org/10.3390/ani16010150 - 5 Jan 2026
Viewed by 296
Abstract
Sex determination and differentiation in teleosts are governed by complex genetic regulatory networks that include evolutionarily conserved mechanisms. In this study, we investigated Boleophthalmus pectinirostris, a Gobiidae species lacking heterogametic sex chromosomes, using comparative gonadal transcriptome analysis to identify sex differentially expressed [...] Read more.
Sex determination and differentiation in teleosts are governed by complex genetic regulatory networks that include evolutionarily conserved mechanisms. In this study, we investigated Boleophthalmus pectinirostris, a Gobiidae species lacking heterogametic sex chromosomes, using comparative gonadal transcriptome analysis to identify sex differentially expressed genes (DEGs). RNA sequencing of ovarian and testicular tissues identified 17,214 DEGs, including 14,302 upregulated in males and 2912 upregulated in females. These DEGs were primarily associated with male (e.g., dmrt1, amh, amhr2) or female (e.g., bmp15, gdf9, rspo1) sex determination and differentiation, steroidogenesis (e.g., hsd17b1, hsd3b1, cyp17a1), and meiosis (e.g., cyp26b1, aldh1a2, piwil2). Functional enrichment analysis revealed that male upregulated DEGs were involved in spermatogenesis pathways such as calcium signaling, while female upregulated DEGs were associated with oogenesis pathways including oocyte meiosis and progesterone-mediated oocyte maturation. Conserved regulators, notably dmrt1 and amh, were predicted to act as key hubs in protein–protein interaction networks, being primarily associated with reproductive processes and sex differentiation in B. pectinirostris. The amh gene produces two alternatively spliced isoforms that differ by a partial deletion in the second exon, both expressed in ovaries and testes. Collectively, this study provides the first comprehensive molecular framework of sex determination and differentiation in Gobiidae species, offering critical insights into the regulatory mechanisms of B. pectinirostris reproductive development. Full article
(This article belongs to the Section Aquatic Animals)
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17 pages, 3911 KB  
Article
Ovarian Developmental Characteristics and Hypothalamic Transcriptomic Analysis of P. leopardus Under Different Aquaculture Modes
by Jingjing Ding, Xin Zhang, Tianyu Jiang, Feng Tang, Liangtao Zheng, Yafeng Tan, Mengmeng Zhang, Jian Luo and Xin Wen
Fishes 2026, 11(1), 30; https://doi.org/10.3390/fishes11010030 - 5 Jan 2026
Viewed by 221
Abstract
Two rearing systems are used for Plectropomus leopardus: sea-cage culture and the land-based flow-through aquaculture system. Cages approximate natural conditions and yield many high-quality eggs but offer limited control over ovarian development; the land-based system is highly controllable yet ovaries develop slowly [...] Read more.
Two rearing systems are used for Plectropomus leopardus: sea-cage culture and the land-based flow-through aquaculture system. Cages approximate natural conditions and yield many high-quality eggs but offer limited control over ovarian development; the land-based system is highly controllable yet ovaries develop slowly and seldom reach full maturity. We compared these systems by analyzing growth–gonad relationships, monthly hormone profiles (GnRH, E2, GnIH), and hypothalamic transcriptomes in 14- and 18-month-old females. Within each system, body weight did not predict gonadal stage and energy allocation was size-independent. In cages, ovaries reached full maturity with normal histology; in tanks, gonads of all sizes remained at stage III, indicating arrested development. Serum GnRH and E2 displayed parallel increases from 12 to 14 months, declined at 16 months and surged at 18 months in both systems, while GnIH fluctuated inversely, suggesting antagonistic control. Transcriptome analysis identified fshr, cyp11a1 and sox17 as key down-regulated genes in tank-reared fish. KEGG (Kyoto Encyclopedia of Genes and Genomes) pathway enrichment implicated GnRH, oxidative phosphorylation, ribosome and Wnt pathways in ovarian progression. These findings elucidate reproductive constraints under artificial conditions and provide molecular targets for controllable breeding of P. leopardus. Full article
(This article belongs to the Special Issue Advances in Fish Reproductive Physiology)
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Article
Evaluation of an Infertile, All-Male ZZ Line Exhibiting Female-like Growth in Chinese Tongue Sole (Cynoglossus semilaevis): Growth Performance, Flesh Quality, and Muscle Metabolome
by Zhangfan Chen, Yinqi Wu, Lanqing Ding, Pengfei Li, Mengqi Wang, Xu Yan, Fangzhou Cheng, He Jiang, Zhongkai Cui and Songlin Chen
Biology 2026, 15(1), 93; https://doi.org/10.3390/biology15010093 - 1 Jan 2026
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Abstract
Chinese tongue sole (Cynoglossus semilaevis) is an important marine aquaculture species that exhibits pronounced female-biased sexual size dimorphism, which limits the economic value of male stocks. The F4 generation of genome-edited dmrt1−/− ZZ males carried a stable 8 bp deletion [...] Read more.
Chinese tongue sole (Cynoglossus semilaevis) is an important marine aquaculture species that exhibits pronounced female-biased sexual size dimorphism, which limits the economic value of male stocks. The F4 generation of genome-edited dmrt1−/− ZZ males carried a stable 8 bp deletion in dmrt1, developed ovarian lamella-like gonads and were completely sterile, as in vitro fertilization with their gonads produced no viable embryos. From 12 to 15 months post-hatch (mph), their growth rate was significantly higher than that of wild-type males and ultimately comparable to that of females. They weighed 3.2-fold heavier and measured 1.38-fold longer than their 15 mph wild-type male counterparts. Muscle nutritional composition and most texture traits of dmrt1−/− ZZ males did not differ from wild-type females. However, their fat content was significantly lower than that of wild-type males, while their Omega6 content was significantly higher. Metabolomic analysis identified 1262 metabolites and revealed differential enrichment of pathways related to amino acids, energy, and antioxidant and neuromuscular metabolism, without evidence of detrimental shifts. Overall, dmrt1 editing yields a fast-growing, functionally sterile male line whose flesh quality is similar to that of wild-type tongue sole, supporting its potential use in sex-control breeding in Chinese tongue sole and providing a valuable model for studying sexual size dimorphism. Full article
(This article belongs to the Section Marine and Freshwater Biology)
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