Handgrip strength and 2D : 4D in women: homogeneous samples challenge the (apparent) gender paradox

The length ratio between the second and the fourth digit (2D : 4D) is a retrospective, non-invasive biomarker for prenatal androgen exposure. It was found to be negatively correlated with handgrip strength (HGS) in men, but the evidence for women is mixed. Such studies in women call for increased detection sensitivity. The present study was designed to reduce potential confounding factors, especially age and ethnicity variation. We measured the digit ratios and HGS of 125 healthy women between 19 and 31 years of age from a remote region in Austria. 2D : 4D of both hands was significantly and negatively correlated with HGS ( n = 125, right hand: r = –0.255, p = 0.002, left hand: r = –0.206, p = 0.011). Size, direction and significance of correlation coefficients remained stable when statistically controlling for age, body weight, body height, body mass index or hours of exercise per week. This yields theory-consistent evidence that HGS and 2D : 4D are clearly associated in women—when sufficiently reducing genetic variation (confounding 2D : 4D), the ontogenetic environment and age ranges (confounding HGS) in the study population. This finding implies similar organizing effects of prenatal androgens as in men, pointing to a more parsimonious developmental mechanism and a new look into its proximate and ultimate causes.

Prenatal androgen exposure alters KNDy neurons and their afferent network in a model of polycystic ovarian syndrome

Polycystic ovarian syndrome (PCOS), the most common endocrinopathy affecting women worldwide, is characterized by elevated luteinizing hormone (LH) pulse frequency due to the impaired suppression of gonadotrophin-releasing hormone (GnRH) release by steroid hormone negative feedback. Although neurons that co-express kisspeptin, neurokinin B and dynorphin (KNDy cells) were recently defined as the GnRH/LH pulse generator, little is understood about their role in the pathogenesis of PCOS. We used a prenatal androgen-treated (PNA) mouse model of PCOS to determine whether changes in KNDy neurons or their afferent network underlie altered negative feedback. First, we identified elevated androgen receptor gene expression in KNDy cells of PNA mice, whereas progesterone receptor and dynorphin gene expression was significantly reduced, suggesting elevated androgens in PCOS disrupt progesterone negative feedback via direct actions upon KNDy cells. Second, we discovered GABAergic and glutamatergic synaptic input to KNDy neurons was reduced in PNA mice. Retrograde monosynaptic tract-tracing revealed a dramatic reduction in input originates from sexually dimorphic afferents in the preoptic area, anteroventral periventricular nucleus, anterior hypothalamic area and lateral hypothalamus. These results reveal two sites of neuronal alterations potentially responsible for defects in negative feedback in PCOS: changes in gene expression within KNDy neurons, and changes in synaptic inputs from steroid hormone-responsive hypothalamic regions. How each of these changes contribute to the neuroendocrine phenotype seen in in PCOS, and the role of specific sets of upstream KNDy afferents in the process, remains to be determined.

Prenatal androgen excess impairs beta cell function by decreased Sirtuin3 expression

Prenatal androgen exposure induces metabolic disorders in female offspring. However, the long-term effect of maternal testosterone excess on glucose metabolism, especially on pancreatic beta cell function, is rarely investigated. Our current study mainly focused on the effects of prenatal testosterone exposure on glucose metabolism and pancreatic beta cell function in aged female offspring. By using maternal mice and their female offspring as animal models, we found that prenatal androgen treatment induced obesity and glucose intolerance in aged offspring. These influences were accompanied by decreased fasting serum insulin concentration, elevated serum triglyceride and testosterone concentrations. Glucose stimulated insulin secretion in pancreatic beta cells of aged female offspring was also affected by prenatal testosterone exposure. We further confirmed that increased serum testosterone contributed to down regulation of Sirtuin 3 expression, activated oxidative stress and impaired pancreatic beta cell function in aged female offspring. Moreover, over-expression of Sirtuin 3 in islets isolated from female offspring treated with prenatal testosterone normalized the oxidative stress level, restored cyclic adenosine monophosphate and adenosine triphosphate generation, which finally improved glucose stimulated insulin secretion in beta cells. Taken together, these results demonstrated that prenatal testosterone exposure caused metabolic disturbance in aged female offspring via suppression of Sirtuin 3 expression and activation of oxidative stress in pancreatic beta cells.

A Systematic Review of Anogenital Distance and Gynecological Disorders: Endometriosis and Polycystic Ovary Syndrome

Background and AimAnogenital distance (AGD) can serve as a life-long indicator of androgen action in gestational weeks 8–14. AGD has been used as an important tool to investigate the exposure to endocrine-disrupting compounds in newborns and in individuals with male reproductive disorder. Endometriosis and polycystic ovary syndrome (PCOS) are two common gynecological disorders and both are related to prenatal androgen levels. Therefore, we performed a systematic review to evaluate the relationships of AGD with these gynecological disorders.MethodsPubMed, Web of Science, and Embase were searched for published studies up to January 25, 2021. No language restriction was implemented.ResultsTen studies were included in this review. Five focused on women with endometriosis, and six investigated women with PCOS. According to these studies, PCOS patients had longer AGD than controls, while endometriosis patients had shorter AGD than controls. In conclusion, this study provides a detailed and accurate review of the associations of AGD with endometriosis and PCOS.ConclusionThe current findings indicate the longer AGD was related to PCOS and shorter AGD was related to endometriosis. However, further well-designed studies are needed to corroborate the current findings.

Premenstrual dysphoric disorder is associated with the longer length from clitoris to urethra

Background Premenstrual dysphoric disorder (PMDD) is a common, recently recognized, psychiatric condition among reproductive women, reflecting abnormal responsivity to ovarian steroids. Moreover, the potential organizational effect of prenatal sex hormones during PMDD has got attentions, but there have been considerably less of researches on this topic. The aim of this research was to investigate the possible role of prenatal androgen in the PMDD. Methods Anogenital distance (AGD), the distance between a woman’s clitoris and her urethral meatus (CUMD), left and right 2D:4D ratios were measured in 77 subjects (25 patients with PMDD), as these anthropometric indicators are considered to indirectly reflect prenatal androgen exposures in utero. Results Patients with PMDD had a longer CUMD than controls (25.03 ± 4.73 vs. 22.07 ± 4.30, P = 0.008), while there were no significant difference between PMDD group and control group in the AGD and right and left 2D:4D ratios. Conclusion Atypical high prenatal androgen exposure might predispose individuals to be susceptible to PMDD.

P–632 Examination of temporal changes in phenotype and gut microbiome during the process of growth in polycystic ovary syndrome (PCOS) model induced by prenatal androgen exposure

Study question From when do abnormality in gut microbiome and phenotypes of PCOS appear during the process of growth? Summary answer Reproductive phenotypes of PCOS appear from 6 weeks and metabolic phenotypes from 12 weeks onward. Alteration in gut microbiome appears as early as 4 weeks. What is known already The etiology of PCOS remains largely unknown, however PCOS is considered as a complex multigenic disorder with strong epigenetic and environmental influence. Previous studies have suggested that fetal over-exposure to androgens could be the main factor of the development of PCOS after birth. On the other hands, recent studies on both human and PCOS rodent models have demonstrated the association between PCOS and alteration of gut microbiome in adulthood. Furthermore, it was recently reported that gut microbiome in obese adolescent with PCOS is different from obese adolescent without PCOS. Study design, size, duration A rodent PCOS model induced by prenatal dehydroepiandrosterone (DHT) exposure was applied to this study. Phenotypes and gut microbiome were compared between PCOS model mice (n = 12/group) and control mice (n = 10/group) at each stage of growth; 4 weeks (prepuberty), 6 weeks (puberty), 8 weeks (adolescent), 12 weeks (young adult), and 16 weeks (adult). The determinants for PCOS phenotypes are onset of puberty, estrous cycle, morphology of ovaries, serum testosterone level, body weight, and insulin resistance. Participants/materials, setting, methods Pregnant dams were subcutaneously injected on days of 16, 17, and 18 of gestation with either sesame oil for control groups or sesame oil containing 250µg of DHT for prenatal DHT groups. The evaluation of PCOS phenotypes and gut microbiome in female offspring were performed at each stage of growth. For examination of gut microbiota, next generation sequencing and bioinformatics analysis of 16S rRNA genes were performed on DNA extracted from mouse fecal samples. Main results and the role of chance Prenatal DHT mice exhibited delayed puberty onset, disrupted estrous cycle, and significantly increased testosterone levels from 6 weeks onward. Significantly increased atretic antral follicles were observed in prenatal DHT mice at 6, 12, and 16 weeks. Prenatal DHT mice showed significantly decreased body weight at 4, 6, 8 weeks and increased body weight from 12 weeks onward. As for gut microbiome, alpha-diversity was significantly different between control and prenatal DHT mice from 8 weeks onward and beta-diversity was significantly different at 6 and 8 weeks. Altered composition of gut microbiota was observed as early as 4 weeks. At phylum level, Firmicutes are significantly increased in prenatal DHT mice at 4 and 8 weeks and decreased at 16 weeks. Actinobacteria phylum showed significant decrease at 6 and 8 weeks in prenatal DHT mice. At genus level, relative abundance of several bacterial taxa significantly differed between control and prenatal DHT mice; some taxa, such as Allobaculum, Adlercreutzia, Bilophila, Clostridium, Gemella, Gemmiger, Roseburia, Ruminococcus, Staphylococcus, and Sutterella, exhibited constant increase or decrease in prenatal DHT mice during the process of growth. Interestingly, Roseburia was never detected in prenatal DHT mice, while approximately half of control mice harbored Roseburia at 12 and 16 weeks. Limitations, reasons for caution It is not clearly determined whether alteration in gut microbiome is cause or result of PCOS development, although the changes in gut microbiome seemed to precede the appearance of typical PCOS phenotypes in the present study. Mouse model does not completely recapitulate human PCOS. Wider implications of the findings: Our findings suggest that prenatal androgen exposure causes alteration of gut microbiome from pre-puberty onward, even before PCOS phenotypes become apparent. Intervention for girls at risk of PCOS with pre/pro-biotics may prevent them from developing PCOS in future. Trial registration number Not applicable

Evidence and Implications From a Natural Experiment of Prenatal Androgen Effects on Gendered Behavior

Sex and gender are key to people’s lives, and are the focus of scientific and popular interest and controversy. Sex-related psychological characteristics reflect more than socialization; they are influenced by sex hormones present during sensitive periods of development, particularly androgens that are present prenatally. Studies of females with congenital adrenal hyperplasia (CAH) show how prenatal androgens affect behavior across the life span; these hormones have large effects on interest and engagement in gendered activities, moderate effects on spatial abilities, and relatively small (or no) effects on gender identity, gender cognitions, and gendered peer involvement. In addition to showing the complexity of androgens’ effects on gendered behavior, studies of females with CAH provide an opportunity to test theories of gender development, gain insight into how nature and nurture work together, and examine mechanisms of development. The implications of this work have often been misunderstood, so we consider what it means—and does not mean—for biology to influence gender-related behavior.

Investigating the reliability and sex differences of digit lengths, ratios, and hand measures in infants

Hands and digits tend to be sexually dimorphic and may reflect prenatal androgen exposure. In the past years, the literature introduced several hand and digit measures, but there is a lack of studies in prepubertal cohorts. The available literature reports more heterogeneous findings in prepubertal compared to postpubertal cohorts. The comparability of the available studies is further limited by the study design and different measurement techniques. The present study compared the reliability and sex differences of available hand and digit measures, namely digit lengths of 2D, 3D, 4D, 5D, digit ratios 2D:4D, 2D:5D, 3D:4D, 3D:5D, 4D:5D, relative digit lengths rel2, rel3, rel4, rel5, directional asymmetry of right and left 2D:4D (Dr-l), hand width, length, and index of 399 male and 364 female 6-month-old German infants within one study using only indirect and computer-assisted measurements. The inter-examiner reliability was excellent while the test-retest reliability of hand scans was only moderate to high. Boys exhibited longer digits as well as wider and longer hands than girls, but smaller digit ratios, with ratios comprising the fifth digit revealing the largest effect sizes. Other hand and digit ratios revealed sex differences to some extent. The findings promote the assumption of sexual dimorphic hand and digit measures. However, by comparing the results of the available literature, there remains an uncertainty regarding the underlying hypothesis. Specifically in prepubertal cohorts, i.e. before the influence of fluctuating hormones, significant effects should be expected. It seems like other factors than the influence of prenatal androgens contribute to the sexual dimorphism in hand and digit lengths.