Effect of epidermal growth factor on steroidogenesis by caprine granulosa cells in culture: interaction with FSH

Besides gonadotrophins various peptide growth factors have been implicated in the ovarian folliculogenesis. In this study, the effect of epidermal growth factor (EGF) (0, 0.1, 1.0, 10ng/ml culture medium) on steroidogenesis by caprine granulosa cells at various stages of maturation was investigated using serum free culture medium. Caprine granulosa cells were obtained from ovarian follicles and classified into three classes: small (<3mm), medium (3-6mm) and large (>6mm in diameter). EGF (10ng/m culture medium) alone reduced estradiol secretion in granulosa cell from small, medium and large follicles by 62, 48 and 29%, respectively, as compared with control. This inhibition was 50, 36 and 21%, respectively, when EGF (10ng/ml culture medium) was applied in combination with FSH (100ng/ml culture medium). EGF alone stimulated the secretion of progesterone in granulosa cells from all the three categories of follicles only at highest dose tested (10ng/ml culture medium). FSH acted synergistically with EGF in stimulating progesterone secretion by cultured granulosa cells. EGF in combination with FSH (100ng/ml culture medium) significantly (P<0.05) stimulated progesterone secretion by cultured granulosa cells from all three categories of follicles even at the lowest dose (0.1ng/ml culture medium) tested. In conclusion, EGF significantly influences the steroidogenesis by caprine granulosa cells in vitro and may play important role in the follicular growth and maturation.