An endogenous ovarian growth factor which stimulates BALB/3T3 and granulosa cell proliferation

Extracts of whole porcine ovary stimulate BALB/3T3 [3H] DNA synthesis in BALB/3T3 cells. Biochemical characterization indicates the growth factor is associated with a soluble cationic protein that is labile to heat, stable to dithiothreitol treatment and elutes from Sephadex G-100 between chymotrypsin (25,000 Mr) and cytochrome C (12,700 Mr). Extracts of thecal tissue have growth-promoting activity in both granulosa and 3T3 cells. Conditioned medium from thecal but not granulosa cell cultures stimulates [3H] DNA synthesis in quiescent 3T3 and granulosa cells. The results indicate the presence of an endogenous protein ovarian growth factor found in the theca that stimulates granulosa cell proliferation in vitro.