Department of Zoology, Mizoram University, Aizawl, Mizoram, India.
J Exp Zool A Ecol Integr Physiol. 2024 Nov;341(9):1021-1029. doi: 10.1002/jez.2857. Epub 2024 Jul 8.
Hyperandrogenemia is associated with polycystic ovarian syndrome (PCOS) and imbalances in the pituitary hormones, luteinizing hormone (LH) and follicle-stimulating hormone (FSH) levels. Apelin and its receptor, APJ (class A, rhodopsin-like G- protein-coupled receptor), belongs to adipokines, and its expression has been shown in the pituitary. It is also well known that, hyperandrogenism and PCOS have deregulation of different adipokines. Whether hyperandrogenism also deregulates the apelin system in the pituitary has yet to be investigated. Thus, we have investigated the expression and localization of apelin and its receptor, APJ, in the letrozole-induced hyperandrogenised pituitary of female mice. Our results showed that the apelin, APJ and androgen receptor (AR) expression were upregulated in the anterior pituitary. Furthermore, the immunostaining of LH exhibited increased abundance than FSH. The circulating LH was also found to be elevated compared to FSH levels. The increased LH synthesis and secretion coincides with elevated apelin system in the pituitary of hyperandrogenised mice. Recently, a direct role of apelin has also been reported in the female pituitary, where apelin inhibits LH secretion. Thus, apelin could be one of the factors for deregulated gonadotropin secretion in hyperandrogenised conditions. However, more research is needed to fully understand the complex interactions between apelin and androgen regarding gonadotropin secretion in hyperandrogenised conditions.
高雄激素血症与多囊卵巢综合征（PCOS）和垂体激素、黄体生成素（LH）和卵泡刺激素（FSH）水平失衡有关。Apelin 及其受体 APJ（A 类，视紫红质样 G 蛋白偶联受体）属于脂肪因子，其在垂体中有表达。众所周知，高雄激素血症和 PCOS 会导致不同脂肪因子的失调。高雄激素血症是否也会使垂体中的 Apelin 系统失调，目前尚未可知。因此，我们研究了 Apelin 及其受体 APJ 在来曲唑诱导的雌性小鼠高雄激素血症垂体中的表达和定位。我们的研究结果表明，Apelin、APJ 和雄激素受体（AR）在前垂体中表达上调。此外，LH 的免疫染色显示其丰度高于 FSH。与 FSH 水平相比，循环 LH 也升高。LH 的合成和分泌增加与高雄激素血症小鼠垂体中 Apelin 系统的升高相一致。最近，也有研究报道 Apelin 在女性垂体中具有直接作用，Apelin 抑制 LH 的分泌。因此，Apelin 可能是高雄激素血症条件下性腺激素分泌失调的因素之一。然而，要充分了解 Apelin 和雄激素在高雄激素血症条件下对促性腺激素分泌的复杂相互作用，还需要进一步的研究。
