Luteinization in primates is accompanied by loss of a 43-kilodalton adenosine 3',5'-monophosphate response element-binding protein isoform.

Although granulosa cell differentiation and corpus luteum function are both regulated by cAMP, there are development-dependent differences, particularly at the level of gene expression and cell proliferation, between the responses of follicular granulosa cells and luteal cells to trophic hormone stimulation. In this study, we sought to determine whether these differences could be due to changes in the cellular expression of cAMP response element (CRE)-binding protein (CREB). Immunocytochemical analysis of macaque ovaries revealed a development-related alteration in the subcellular distribution of CREB-immunoreactive material. Immunoreactive CREB was present in nuclei of follicular granulosa cells from maturing follicles, whereas after ovulation and luteinization, no CREB-immunoreactive proteins were visualized in luteal cell nuclei. Anti-CREB immunoblotting of granulosa cell extracts from macaque preovulatory follicles as well as extracts of granulosa cells from luteinizing human follicles revealed a 43-k...