Prostaglandin involvement in follicle-stimulating hormone-induced proliferation of granulosa cells from chicken prehierarchical follicles

The aim of the present study was to evaluate the role of prostaglandin (PG) on proliferation of granulosa cells from prehierarchical small yellow follicles (SYF) of buff laying hens. The granulosa layers were separated by mechanic method and dispersed into single cells. After 16 h pre-incubation in 0.5% FCS medium, the medium was replaced with serum-free medium, which was supplemented with 10 microg/ml insulin, 5 microg/ml transferrin and 3 x 10(-8)M selenite. Cells were challenged with PGE1 and FSH for 24 h and then assessed for proliferation. The results showed that PGE(1) (0.1-10 ng/ml) had a similar proliferating effect as FSH on granulosa cells, and these stimulating effects were restrained by the PGE receptor antagonist SC19220 at 10(-7) to 10(-5)M. Prostaglandin synthase antagonist indomethacin (10(-7) to 10(-5)M) suppressed FSH-induced increase in the number of granulosa cells in a dose-dependent manner. Downstream activation of protein kinase A by forskolin-activated adenylate cyclase resulted in elevated proliferation of granulosa cells, an effect unobserved by phorbol-12-myristrate-13-acetate-activated protein kinase C. In addition, PGE1-stimulated proliferation of granulosa cells was hindered by H89 (PKA inhibitor) but not by H7 (PKC inhibitor). Furthermore, the proliferating cell nuclear antigen labeling index (PCNA-LI) of granulosa cells displayed similar changes with the number of cells. These results indicated that PGE1 promoted the proliferation of granulosa cells from SYF and was also involved in mediating FSH-stimulated intracellular PKA signal transduction.