A regulatory role of androgen in ovarian steroidogenesis by rat granulosa cells

Abstract

Excess androgen and insulin-like growth factor (IGF)-I in the ovarian follicle has been suggested to be involved in the pathophysiology of polycystic ovary syndrome (PCOS). Here we investigated the impact of androgen and IGF-I on the regulatory mechanism of ovarian steroidogenesis using rat primary granulosa cells. It was revealed that androgen treatment with dihydrotestosterone (DHT) amplified progesterone synthesis in the presence of FSH and IGF-I, whereas it had no significant effect on estrogen synthesis by rat granulosa cells. In accordance with the effects of androgen on steroidogenesis, DHT enhanced the expression of progesterogenic factors and enzymes, including StAR, P450scc and 3βHSD, and cellular cAMP synthesis induced by FSH and IGF-I. Of note, treatment with DHT and IGF-I suppressed Smad1/5/8 phosphorylation and transcription of the BMP target gene Id-1, suggesting that androgen and IGF-I counteract BMP signaling that inhibits FSH-induced progesterone synthesis in rat granulosa cells. DHT was revealed to suppress the expression of BMP-6 receptors, consisting of ALK-2, ALK-6 and ActRII, while it increased the expression of inhibitory Smads in rat granulosa cells. In addition, IGF-I treatment upregulated androgen receptor (AR) expression and DHT treatment suppressed IGF-I receptor expression on rat granulosa cells. Collectively, the results indicate that androgen and IGF-I mutually interact and accelerate progesterone production, at least in part, by regulating endogenous BMP signaling in rat granulosa cells. Cooperative effects of androgen and IGF-I counteract endogenous BMP-6 activity in rat granulosa cells, which is likely to be functionally linked to the steroidogenic property shown in the PCOS ovary.

Interaction of ovarian steroidogenesis and clock gene expression modulated by bone morphogenetic protein-7 in human granulosa cells

“…In the present experiments, it was found that BMP-7 affected the levels of 3βHSD expression rather than StAR, though this discrepancy could be due to the characteristic differences between rat primary granulosa cells and human KGN cells. As other humoral modulators related to ovarian steroidogenesis, androgens [15], incretins [16], orexins [17] and melatonin [35], which can affect endogenous BMP-Smad signaling activity in granulosa cells [36,37], may also be involved in the modulation of Clock gene expression in the ovary. Further studies are necessary to determine the functional interaction between the activities of Clock-related molecules and ovarian steroidogenesis.…”

“…KGN cells (1 × 10 5 cells/mL) were treated with forskolin (1 μM) or BMPs (100 ng/mL) in 12-well plates containing serum-free DMEM/F12 for the indicated periods. Concentrations of forskolin and BMP ligands used in the current experiments were selected based on our earlier data obtained from the same in vitro experiments [14][15][16][17]. Total cellular RNA was extracted using TRI Reagent ® (Cosmo Bio Co., Ltd., Tokyo, Japan) and the concentration of extracted RNA were determined by NanoDrop TM One spectrophotometer (Thermo Fisher Scientific, Waltham, MA).…”

“…Total cellular RNA was extracted using TRI Reagent ® (Cosmo Bio Co., Ltd., Tokyo, Japan) and the concentration of extracted RNA were determined by NanoDrop TM One spectrophotometer (Thermo Fisher Scientific, Waltham, MA). Primer pairs for detecting the following genes: steroidogenic acute regulatory protein (StAR), steroid side-chain cleavage enzyme (P450scc), 3β-hydroxysteroid dehydrogenase (3βHSD), aromatase (P450arom), and a housekeeping gene, ribosomal protein L19 (RPL19), were utilized as we earlier reported [13,[15][16][17][18][19]. Other primers were also selected from different exons to eliminate PCR products originated from chromosomal DNA as follows: 966-985 and 1,099-1,118 for Bmal1 (from GenBank accession #AB000812); 2,072-2,091 and 2,262-2,281 for Clock (NM_001267843); 1,614-1,633 and 1,870-1,889 for Per2 (NM_0022817); and 2,203-2,222 and 2,461-2,480 for Cry1 (NM_ 004075).…”

Modulation of bone morphogenetic protein activity by melatonin in ovarian steroidogenesis

“…The effects of various factors that can affect FSH‐induced steroidogenesis were investigated further (Figure ). Among the examined factors, androgens, growth hormone, and insulin‐like growth factor‐I were found to be key molecules that induce smad6/7expression. In contrast, prolactin (PRL), somatostatins, and incretins were found to be suppressors of inhibitory smad6/7 expression in the granulosa cells (Figure ).…”

Bisphenol-A Dose-dependently Regulates The Development of Ovary and Uterus through Differential Expression of METTL3

“…Hyperandrogenism is one of the cardinal features of PCOS. Both clinical and laboratory studies have revealed that the over production of androgen is correlated to the expression of androgen synthases in the ovary [4,5], such as CYP17, CYP11, StAR [6], HSD3B [7] and other proteases. It has been found that CYP11A1(tttta)n repeat polymorphism may be a potential molecular marker of PCOS risk [8,9].…”