Immunolocalization of androgen receptor and steroidogenic enzymes in cumuli oophori of pre- and post-ovulatory rats

Immunolocalization of 3 beta-hydroxysteroid dehydrogense (3 beta-HSD), cytochrome P450c17 (P450c17) and androgen receptor (AR) were investigated in rat cumuli oophori (COCs) of late pre-ovulatory follicles and in post-ovulatory COCs bearing fertilized oocytes A gradient of intensity of 3 beta-HSD immunolabelling was observed in the granulosa layer of pre ovulatory follicles, with almost negative immunolabel ling in COCs and with the strongest immunoreaction in the mural granulosa cells Post ovulatory COCs showed strong 3 beta HSD immunolabelling in the peripheral regions and weak labelling near the oocyte, suggestive of responsiveness of cumulus cells to an anti luteinizing effect exerted by the fertilized oocyte In pre ovulatory follicles, a weak P450c17 immunopositivity was limited to expanded cumulus granulosa cells and the positive labelling persisted in post ovulatory COCs P450c17 immunopositivity was also found in ampullary epithelial cells A strong AR immunopositivity was confined mainly to the COCs in pre ovulatory follicles and a similar immunoreaction was present in the granulosa cells of ovulated COCs Simultaneous AR and cytochrome P450c17 immunolabelling in the pre and post ovulatory COCs is suggestive of an intra and paracrine androgen regulation of the cumulus granulosa cell function (C) 2009 Elsevier GmbH All rights reserved