Signal transduction of stem cell factor in promoting early follicle development.

Stem cell factor (SCF), another alternative name is kit ligand, is essential for the development of early follicles. However, the underlying molecular mechanism remains to be defined. By using cultured ovaries that are rich in primordial follicles, the action of SCF (kit ligand) on early follicular development and the activated signal transduction pathways were investigated. SCF (kit ligand) promoted early follicle development. PKC and MEK but not PKA were involved in the signal transduction of SCF (kit ligand) as indicated by results using their specific pharmacological inhibitors. SCF (kit ligand) also enhanced the phosphorylation of two MEK substrates, Erk1 and 2 (Erk1/2) in thecal-interstitial cells where PKC might play an important role indicated by results using its inhibitors. SCF (kit ligand) elevated the expression of steroidogenic factor 1 (SF-1) in thecal-interstitial cells probably through a pathway that consists of Erk1/2. These results suggest that SCF (kit ligand) promotes follicular growth by stimulating the function of thecal-interstitial cells through the Erk1/2 pathway.