Molecular determinants of sexual differentiation

Cyclopiazonic acid suppresses the function of Leydig cells in prepubertal male rats by disrupting mitofusin 1-mediated mitochondrial function

This research investigated the impact of cyclopiazonic acid (CPA), a mycotoxin, on the function of progenitor Leydig cells (PLCs) in prepubertal male rats, focusing on its potential disruption of mitochondrial integrity through mitofusin 1 (MFN1) modulation. In vivo, Sprague Dawley rats received CPA (0.2, 1, 5 mg/kg/day) via gavage from postnatal days 21-28 to evaluate PLC function and mitochondrial morphology using serum hormone levels, histology, qPCR, and Western blot analyses. In vitro, rat R2C cells were treated with CPA (0.1, 1, 10 μM) alone or in combination with 100 μM leflunomide to assess PLC development through testosterone measurements, Western blotting, flow cytometry, and Mito-Tracker Green Staining. The findings from in vivo experiments showed that CPA reduced serum testosterone and progesterone levels at 1 mg/kg/day. The qPCR and Western blotting analyses revealed significant alterations in the expression of genes and proteins pertinent to PLC function, such as Scarb1, Star, Cyp11a1, and Cyp17a1. Immunofluorescence staining further revealed a reduction in MFN1 expression following exposure to CPA. In vitro experiments corroborated these observations, demonstrating that CPA induced mitochondrial fragmentation by downregulating SIRT1, PGC1-α, MFN1, and OPA1, increase reactive oxygen species, and inhibit testosterone synthesis in R2C cells. The administration of leflunomide was shown to mitigate the detrimental effects of CPA on PLCs. In conclusion, this research sheds new light on the deleterious effects of CPA on the reproductive development of prepubertal males.

Patulin Stimulates Progenitor Leydig Cell Proliferation but Delays Its Differentiation in Male Rats during Prepuberty

Patulin is a mycotoxin with potential reproductive toxicity. We explored the impact of patulin on Leydig cell (LC) development in male rats. Male Sprague Dawley rats (21 days postpartum) were gavaged patulin at doses of 0.5, 1, and 2 mg/kg/day for 7 days. Patulin markedly lowered serum testosterone at ≥0.5 mg/kg and progesterone at 1 and 2 mg/kg, while increasing LH levels at 2 mg/kg. Patulin increased the CYP11A1+ (cholesterol side-chain cleavage, a progenitor LC biomarker) cell number and their proliferation at 1 and 2 mg/kg. Additionally, patulin downregulated Lhcgr (luteinizing hormone receptor), Scarb1 (high-density lipoprotein receptor), and Cyp17a1 (17α-hydroxylase/17,20-lyase) at 1 and 2 mg/kg. It increased the activation of pAKT1 (protein kinase B), pERK1/2 (extracellular signal-related kinases 1 and 2), pCREB (cyclic AMP response binding protein), and CCND1 (cyclin D1), associated with cell cycle regulation, in vivo. Patulin increased EdU incorporation into R2C LC and stimulated cell cycle progression in vitro. Furthermore, patulin showed a direct inhibitory effect on 11β-HSD2 (11β-hydroxysteroid dehydrogenase 2) activity, which eliminates the adverse effects of glucocorticoids. This study provides insights into the potential mechanisms via which patulin affects progenitor LC development in young male rats.

Low dose of fire retardant, 2,2',4,4'-tetrabromodiphenyl ether (BDE47), stimulates the proliferation and differentiation of progenitor Leydig cells of male rats during prepuberty

2,2',4,4'-Tetrabromodiphenyl ether (BDE47), a flame retardant, is extensively distributed in the food chain. However, whether BDE47 affects Leydig cell development during prepuberty remains unclear. BDE47 was daily gavaged to 21-day-old Sprague-Dawley male rats with 0 (corn oil), 0.1, 0.2, and 0.4 mg/kg for 14 days. BDE47 did not affect the body weight or testis weight of rats. It significantly increased serum testosterone level at 0.4 mg/kg, but decreased luteinizing hormone (LH) level without affecting estradiol level. BDE47 induced Leydig cell hyperplasia (the number of CYP11A1-positive Leydig cells increased), and up-regulated the expression of Scarb1, Star, Hsd11b1, Pcna, and Ccnd1 in the testis. BDE47 significantly reduced p53 and p21 levels but increased CCND1 level. It also markedly increased the phosphorylation of AKT1, AKT2, ERK1/2, and CREB. BDE47 significantly up-regulated the expression of Scarb1, Star, and Hsd11b1 and stimulated androgen production by immature Leydig cells from rats under basal, LH, and 8Br-cAMP stimulated conditions at 100 nM in vitro. In conclusion, BDE47 increased Leydig cell number and up-regulated the expression of Scarb1 and Star, thereby leading to increased testosterone synthesis.

Hormonal correlates of male life history stages in wild white-faced capuchin monkeys (Cebus capucinus)

Much attention has been paid to hormonal variation in relation to male dominance status and reproductive seasonality, but we know relatively little about how hormones vary across life history stages. Here we examine fecal testosterone (fT), dihydrotestosterone (fDHT), and glucocorticoid (fGC) profiles across male life history stages in wild white-faced capuchins (Cebus capucinus). Study subjects included 37 males residing in three habituated social groups in the Área de Conservacíon Guanacaste, Costa Rica. Male life history stages included infant (0 to <12months; N=3), early juvenile (1 to <3years; N=10), late juvenile (3 to <6years; N=9), subadult (6 to <10years; N=8), subordinate adult (⩾10years; N=3), and alpha adult (⩾10years; N=4, including one recently deposed alpha). Life history stage was a significant predictor of fT; levels were low throughout the infant and juvenile phases, doubled in subadult and subordinate adults, and were highest for alpha males. Life history stage was not a significant predictor of fDHT, fDHT:fT, or fGC levels. Puberty in white-faced capuchins appears to begin in earnest during the subadult male phase, indicated by the first significant rise in fT. Given their high fT levels and exaggerated secondary sexual characteristics, we argue that alpha adult males represent a distinctive life history stage not experienced by all male capuchins. This study is the first to physiologically validate observable male life history stages using patterns of hormone excretion in wild Neotropical primates, with evidence for a strong association between fT levels and life history stage.

A practical approach to intersex in the newborn period

Sexual determination is a complex process that occurs in an organized sequential manner. When chromosomal, gonadal, or phenotypic sex determination goes awry,intersexuality develops. Advances in molecular biology have made it easier to understand the various phenotypes that are encountered. It is easy to be overwhelmed when reviewing the testosterone synthesis pathway and the intersex differential diagnosis. This article presents a useful approach to the evaluation of the newborn with ambiguous genitalia.

Insights into causes of sexual ambiguity

Our understanding of the causes of sexual ambiguity has progressed from the determination of the hormonal etiologies to defining the genetic basis of intersex disorders. The localization of specific genes involved in the process of sexual differentiation has made it possible to determine the mutations and other molecular events that result in sexual ambiguity. With this information, some disorders can now be diagnosed before birth and possibly even treated in utero.