Objective: To investigate the effect of leptin on the actions of growth hormone (GH) and insulin-like growth factor-I (IGF-I) in ovarian steroidogenesis in vitro.
Design: In vitro cell culture study.
Setting: Research laboratory of a university hospital.
Patient(s): Luteinized granulosa cells (GC) were obtained from 20 healthy women undergoing ovarian stimulation for IVF treatment.
Intervention(s): Granulosa cells were cultured in serum free conditions for 72 hours with either GH or IGF-I, or their combination, in the absence or presence of leptin (1, 10, and 100 ng/mL).
Main outcome measure(s): At 24 and 72 hours of the culture estradiol (E(2)) and progesterone (P) concentrations were measured in culture supernatants by enzyme immunoassays.
Result(s): Leptin at the doses of 1 and 10 ng/mL significantly stimulated, whereas at the dose of 100 ng/mL it significantly suppressed E(2) and P production as compared to control. Estradiol production was significantly stimulated by both GH (72 hours) and IGF-I (24 and 72 hours) and that of P only by IGF-I (72 hours). Leptin at the low doses enhanced, whereas at the high dose it suppressed the effect of GH or IGF-I on E(2) and P synthesis.
Conclusion(s): These results demonstrate for the first time that leptin can modulate the effect of GH on steroids production by human luteinized GC in culture.