Role of resistin in the porcine uterus: effects on endometrial steroidogenesis.

Context The adipose tissue produces adipokines - hormones essential to many biological functions, including reproduction. Aims We hypothesised that resistin, one of the adipokines, is present in the blood plasma, uterine luminal flushings (ULF) and uterus of pigs during the oestrous cycle and early pregnancy, and that resistin influences uterine steroidogenesis. Methods This study aimed to determine the expression of resistin in the porcine endometrium and myometrium during the cycle and pregnancy by quantitative real-time polymerase chain reaction and western blot (WB). The adipokine concentrations in blood plasma and ULF were defined by enzyme-linked immunosorbent assay. The impact of resistin on progesterone (P4 ) and oestradiol (E2 ) secretion and steroidogenic enzyme proteins' expression were determined by radioimmunoassay and WB, respectively. The effect of resistin on protein kinase B (Akt) protein phosphorylation was determined by WB. Key results The study's results identified the resistin gene and protein expression in the porcine endometrium and myometrium. Moreover, the expression of adipokine in the uterus, its concentrations in the blood plasma and ULF, and its impact on the endometrial P4 and E2 production, are dependent on the hormonal milieu related to the phase of the cycle and/or period of pregnancy. Furthermore, resistin enhances the phosphorylation of the Akt signaling pathway. Conclusions The current findings suggest that resistin may control the steroidogenesis process in the porcine endometrium and could be an important regulator of pig reproduction. Implications In the long-term perspective, the results obtained in this study may help improve farm animal breeding.