Effect of adiponectin on the steroidogenic acute regulatory protein, P450 side chain cleavage enzyme and 3β-hydroxysteroid dehydrogenase gene expression, progesterone and androstenedione production by the porcine uterus during early pregnancy.

Adiponectin and its receptors are expressed in the human and porcine uterus and this endocrine system has important role in the regulation of reproductive processes. The expression of steroidogenic acute regulatory protein (StAR) and 3β-hydroxysteroid dehydrogenase (HSD3B1) were observed in the human and porcine uterus during the oestrous cycle and pregnancy. The de novo synthesis of steroids in the uterus might be a crucial factor for effective implantation and maintenance of pregnancy. We hypothesized that adiponectin modulates the expression of key enzymes in the synthesis of the steroids: StAR, P450 side chain cleavage enzyme (CYP11A1) and HSD3B1, as well as progesterone (P4) and androstenedione (A4) secretion by the porcine uterus. Endometrial and myometrial explants harvested from gilts (n = 5) on days 10 to 11, 12 to 13, 15 to 16 and 27 to 28 of pregnancy and on days 10 to 11 of the oestrous cycle were cultured in vitro in the presence of adiponectin (1, 10 μg/ml), adiponectin with insulin (10 ng/ml) and insulin alone (10 ng/ml). Gene expression was examined by real-time PCR, and the secretion of the steroids was determined by radioimmunoassay. The content of StAR, CYP11A1 and HSD3B1 mRNAs and the secretion of P4 and A4 was modulated by adiponectin in endometrial and myometrial tissue explants during early pregnancy and the oestrous cycle. In this action adiponectin interacted with insulin. Insulin itself also regulated the steroidogenic activity of the porcine uterus. ere we reported, for the first time, the expression of CYP11A1 genes in the porcine endometrium and myometrium. Our novel findings indicate that adiponectin affects basal and insulin-stimulated expression of key steroidogenic genes and production of steroid hormones by the porcine uterus during maternal recognition of pregnancy and implantation.