Cytochemical localization of adenylate cyclase in bovine cumulus-oocyte complexes.

The ultrastructural localization of adenylate cyclase was studied in bovine cumulus-oocyte complexes. Adenylate cyclase was observed on the plasma membrane of the oocyte and occasionally on the plasma membrane of cumulus cells. The cytochemical observations presented demonstrate that there is more adenylate cyclase in cumulus-oocyte complexes after in vitro stimulation with forskolin. The presence of adenylate cyclase upon the oocyte was more pronounced. In addition adenylate cyclase appeared to be localized on the cumulus cells, especially between junctional complexes of cumulus cells and on cumulus cell processes contacting the oocyte. The cumulus cells never showed the presence of adenylate cyclase in the absence of forskolin. No changes in the presence of adenylate cyclase were observed during in vitro meiotic maturation.