Adiponectin Expression in the Porcine Ovary during the Oestrous Cycle and Its Effect on Ovarian Steroidogenesis

Abstract

Adiponectin is an adipose-secreted hormone that regulates energy homeostasis and is also involved in the control of the reproductive system. The goal of the present study was to investigate changes in adiponectin gene and protein expression in porcine ovarian structures during the oestrous cycle and to examine the effects of in vitro administration of adiponectin on basal and gonadotrophin- and/or insulin-induced secretion of ovarian steroid hormones. Both gene and protein expression of adiponectin were enhanced during the luteal phase of the cycle. Adiponectin affected basal secretion of progesterone by luteal cells, oestradiol by granulosa cells, and testosterone by theca interna cells. The gonadotrophin/insulin-induced release of progesterone from granulosa and theca interna cells and the release of oestradiol and androstenedione from theca cells was also modified by adiponectin. In conclusion, the presence of adiponectin mRNA and protein in the porcine ovary coupled with our previous results indicating adiponectin receptors expression suggest that adiponectin may locally affect ovarian functions. The changes in adiponectin expression throughout the oestrous cycle seem to be dependent on the hormonal status of pigs related to the stage of the oestrous cycle. The effect of adiponectin on ovarian steroidogenesis suggests that this adipokine influences reproductive functions in pigs.

Adiponectin protects against development of metabolic disturbances in a PCOS mouse model

“…Experimental data supporting a direct effect of adiponectin on ovarian function is inconsistent, and research has mainly been performed in vitro (22). In line with our observation of high estradiol levels in APNtg mice, another study has found that high doses of adiponectin stimulates basal secretion of estradiol from porcine granulosa cells (56). In this same study, researchers observed decreases in testosterone secretion by adiponectin exposure.…”

The influence of adiponectin on the transcriptomic profile of porcine luteal cells

“…Ledoux et al (2006) observed higher levels of prostaglandin-endoperoxide synthase 2 (PTGS2), prostaglandin E synthase (PTGES), and vascular endothelial growth factor (VEGF) gene expression in granulosa cells primed with adiponectin, an increase in the expression of the steroidogenic acute regulatory protein (StAR) gene, and a decrease in the expression of the P450 aromatase gene in granulosa cells derived from prepubertal gilts. Adiponectin was also found to affect the basal and stimulated secretion of steroid hormones, i.e., progesterone, estradiol, androstenedione, and testosterone, by ovarian cells of mature gilts (Maleszka et al 2014a). These results undoubtedly confirm the involvement of adiponectin in the functioning of the reproductive system.…”

“…The mid-luteal phase is characterized by the highest activity of CL, an endocrine gland secreting estrogens and, most of all, significant amounts of progesterone. Adiponectin had an inhibitory effect on in vitro secretion of progesterone by porcine luteal cells on days 10 to 12 of the estrous cycle (Maleszka et al 2014a). The effect of adiponectin on ovarian basal progesterone secretion was also suggested in studies on cows, rats, and humans (Chabrolle et al 2009;Mailard et al 2010;Lagaly et al 2008).…”

“…The expression of adiponectin receptors was also found in the pituitary gland, which allows for the direct effect of the hormone on the secretion of the luteinizing hormone and follicle-stimulating hormone (Rodriguez-Pacheco et al 2007;Kiezun et al 2014). Another proof for the involvement of adiponectin in the regulation of the HPG axis is the demonstrated presence of adiponectin receptor protein in human and pig ovaries (Chabrolle et al 2009;Maleszka et al 2014a).…”

“…It plays a dominant role in lipid and carbohydrate metabolism by stimulating fatty acid oxidation, decreasing plasma triglycerides, and increasing cells' sensitivity to insulin and has direct antiatherosclerotic effects (Kadowaki and Yamauchi 2005). Adiponectin is also involved in the regulation of energy balance and body weight and additionally plays a modulatory role in the regulation of the reproductive system (Yamauchi et al 2001;Kiezun et al 2014;Maleszka et al 2014a).…”