Deletion of Androgen Receptor in LepRb Cells Improves Estrous Cycles in Prenatally Androgenized Mice

The ventral premammillary nucleus at the interface of environmental cues and social behaviors

The survival of species heavily depends on social behaviors, which in turn rely on the ability to recognize conspecifics within an appropriate environmental context. These behaviors are regulated by the hypothalamus, which processes signals from both the external environment (such as food availability, photoperiod, and chemical cues from other animals) and the internal state (including sex, estrous cycle stage, nutritional status, and levels of stress). Understanding the brain circuits responsible for specific behaviors in experimental animals is a complex task given the intricate interactions between these factors and the diverse behavioral strategies employed by different species. In this review, we will critically evaluate recent studies focused on the ventral premammillary nucleus (PMv) and discuss findings that reveal the PMv as a key, yet sometimes overlooked, node in integrating external and internal environmental cues. We will examine its structural components, internal connectivity, humoral influences, and associated functions, demonstrating the PMv role in the neural regulation of neuroendocrine responses and social behaviors. While much of the existing research centers on rats and mice as model organisms, we will highlight relevant species differences and include a dedicated section for findings in other species.

Metabolomics and transcriptomics analyses reveal the complex molecular mechanisms by which the hypothalamus regulates sexual development in female goats

BACKGROUND

The hypothalamus is a critical organ that regulates sexual development in animals. However, current research on the hypothalamic regulation of sexual maturation in female goats remains limited. In this study, we conducted metabolomic and transcriptomic analyses on the hypothalamic tissues of female Jining grey goats at different stages of sexual development (1 day old (neonatal, D1, n = 5), 2 months old (prepuberty, M2, n = 5), 4 months old (sexual maturity, M4, n = 5), and 6 months old (breeding period, M6, n = 5)).

RESULTS

A total of 418 differential metabolites (DAMs) were identified in this study, among which the abundance of metabolites such as anserine, L-histidine, carnosine, taurine, and 4-aminobutyric gradually increased with the progression of sexual development. These metabolites may regulate neuronal development and hormone secretion processes by influencing the metabolism of histidine and phenylalanine. Through combined transcriptomic and metabolomic analyses, we identified that differentially expressed genes such as mitogen-activated protein kinase kinase kinase 9 (MAP3K9), prune homolog 2 with BCH domain (PRUNE2), and potassium voltage-gated channel interacting protein 4(KCNIP4) may jointly regulate the development and energy metabolism of hypothalamic Gonadotropin-releasing hormone neurons in conjunction with DAMs, including LPC22:5, 2-Arachidonyl Glycerol ether, LPE22:5, and Lysops22:5. Additionally, we elucidated the molecular mechanism through which glutathione metabolism regulates sexual maturation in goats.

CONCLUSIONS

In summary, this study illustrates the dynamic changes in metabolites and mRNA within hypothalamic tissue during postnatal sexual maturation in female Jining grey goats. This research may provide significant scientific insights for future animal breeding.

Androgen receptor actions on AgRP neurons are not a major cause of reproductive and metabolic impairments in peripubertally androgenized mice

Excess levels of circulating androgens during prenatal or peripubertal development are an important cause of polycystic ovary syndrome (PCOS), with the brain being a key target. Approximately half of the women diagnosed with PCOS also experience metabolic syndrome; common features including obesity, insulin resistance and hyperinsulinemia. Although a large amount of clinical and preclinical evidence has confirmed this relationship between androgens and the reproductive and metabolic features of PCOS, the mechanisms by which androgens cause this dysregulation are unknown. Neuron-specific androgen receptor knockout alleviates some PCOS-like features in a peripubertal dihydrotestosterone (DHT) mouse model, but the specific neuronal populations mediating these effects are undefined. A candidate population is the agouti-related peptide (AgRP)-expressing neurons, which are important for both reproductive and metabolic function. We used a well-characterised peripubertal androgenized mouse model and Cre-loxP transgenics to investigate whether deleting androgen receptors specifically from AgRP neurons can alleviate the induced reproductive and metabolic dysregulation. Androgen receptors were co-expressed in 66% of AgRP neurons in control mice, but only in <2% of AgRP neurons in knockout mice. The number of AgRP neurons was not altered by the treatments. Only 20% of androgen receptor knockout mice showed rescue of DHT-induced androgen-induced anovulation and acyclicity. Furthermore, androgen receptor knockout did not rescue metabolic dysfunction (body weight, adiposity or glucose and insulin tolerance). While we cannot rule out developmental compensation in our model, these results suggest peripubertal androgen excess does not markedly influence Agrp expression and does not dysregulate reproductive and metabolic function through direct actions of androgens onto AgRP neurons.

Androgen excess: a hallmark of polycystic ovary syndrome

Polycystic ovarian syndrome (PCOS) is a metabolic, reproductive, and psychological disorder affecting 6-20% of reproductive women worldwide. However, there is still no cure for PCOS, and current treatments primarily alleviate its symptoms due to a poor understanding of its etiology. Compelling evidence suggests that hyperandrogenism is not just a primary feature of PCOS. Instead, it may be a causative factor for this condition. Thus, figuring out the mechanisms of androgen synthesis, conversion, and metabolism is relatively important. Traditionally, studies of androgen excess have largely focused on classical androgen, but in recent years, adrenal-derived 11-oxygenated androgen has also garnered interest. Herein, this Review aims to investigate the origins of androgen excess, androgen synthesis, how androgen receptor (AR) signaling mediates adverse PCOS traits, and the role of 11-oxygenated androgen in the pathophysiology of PCOS. In addition, it provides therapeutic strategies targeting hyperandrogenism in PCOS.