Immunohistochemical localization of inhibin subunits in polycystic ovary.

The immunohistochemical localization of the alpha-, beta A-, and beta B-subunits of inhibin was examined in polycystic ovary (PCO). The granulosa cells in multicystic follicles in the PCO exhibited negative immunostaining for alpha-subunit and positive staining for beta A- and beta B-subunits. In contrast, the hyperplastic thecal cells exhibited distinct positive staining for alpha-, beta A-, and beta B-subunits. The luteinized stromal cells (stromal hyperthecosis) also exhibited positive staining for each inhibin subunit. The granulosa cells in the tertiary follicle exhibited negative staining for alpha-subunit and positive staining for beta A- and beta B-subunits. No staining for each inhibin subunit was observed in the thecal layer in the tertiary follicle. The present findings suggest that immunoreactive inhibin alpha-, beta A-, and beta B-subunits are present in hyperplastic thecal and stromal cells in PCO, and that granulosa cells in the follicular cyst of PCO might not produce inhibin, in contrast to the normal ovary.