Cyclic adenosine monophosphate promotes the proliferation of chicken granulosa cells in culture

Abstract

The aim of this study was to determine if cAMP regulates the proliferation of chicken granulosa cells and if there is a difference in the effects of cAMP on the granulosa cell proliferation between the largest follicle (F1) and the smaller follicles. Granulosa cells collected from F1 and the third largest follicle (F3) were cultured in medium M199 containing 1% calf serum with or without dibutyryl cAMP (dbcAMP). Proliferation of granulosa cells of F1 was promoted by dbcAMP in a dose-dependent manner. The most effective concentration of dbcAMP to promote the granulosa cell proliferation was 2 m M. In the culture without dbcAMP, the number of the granulosa cells was not changed significantly for 6 days, whereas, in the presence of 2 m M dbcAMP, the number of the granulosa cells was markedly increased during 2 to 6 days. The proliferation of the granulosa cells of F3 was stimulated by dbcAMP in the same manner as that of F1. Morphologically, the granulosa cells of F1 and F3 cultured for 2 days had a sheet-like appearance in control culture, whereas they were contracted, leaving finger-like cytoplasmic processes attached to the adjacent cells and substratum in the presence of 2 m M dbcAMP. After 6 days culture, approximately 90% of the cells of F1 stained positive for 3β-hydroxysteroid dehydrogenase activity in 2 m M dbcAMP-containing culture, whereas only about 20% of the cells were positive in control culture. These results suggest that cAMP promotes the proliferation of the granulosa cells during the follicular growth and this response of granulosa cells to cAMP is similar for F1 and F3.