Effects of testosterone and 2-hydroxyflutamide on progesterone receptor expression in porcine ovarian follicles in vitro

Abstract

The purpose of the study was to test the possible role of the androgen receptor (AR) agonist (testosterone; T), an AR antagonist (2-hydroxyflutamide; 2-Hf) or combination of both (T+2-Hf) on progesterone receptor (PGR) expression in cultured porcine granulosa cells (GCs) or whole follicles. GCs isolated from mature pig follicles (6-8mm in diameter) were cultured for 48 h. Experimental cultures were carried out with the addition of T (10(-7)M), 2-Hf (1.7×10(-4)M) or both T and 2-Hf for the last 24 h of culture. To better imitate in vivo conditions, isolated whole porcine follicles (6-8mm in diameter) were cultured for 24 h in an organ culture system, with the addition of the same factors. The cells or sections obtained from cultured follicles were processed for PGR immunocytochemical or immuno-histochemical staining. In addition, expression of PGR protein was determined by Western blot and progesterone (P(4)) concentrations in the culture media were measured by a radioimmunoassay. We found that isoform A of PGR is expressed in both granulosal and follicular cultures. The 2-Hf in the presence of T increased PGR protein expression in porcine GCs and whole follicles. In both granulosal and follicular cultures, 2-Hf or T alone inhibited P(4) secretion, but simultaneous addition of 2-Hf and T increased P(4) secretion. Our results indicate that androgens may be involved in the control of PGR expression in porcine GCs in vitro. Moreover, we suggest a potential auto/paracrine regulation of the follicular function by androgen-dependent signaling pathway.