Adiponectin increases insulin-like growth factor I-induced progesterone and estradiol secretion in human granulosa cells

Objective: To identify adiponectin and its receptors (AdipoR1 and AdipoR2) in human granulosa cells (GC) and to study the effects of recombinant human adiponectin on P and E-2 secretion from these cells. Design: The effects of recombinant human adiponectin on the secretion of P and E-2 by cultured human GCs were investigated. Setting: Academic institutions. Patient(s): Seventeen infertile and healthy women undergoing IVF. Intervention(s): Primary human GC cultures stimulated with human recombinant adiponectin (5 mu g/mL). Main Outcome Measure(s): Determination of messenger RNA (mRNA) and protein expression of adiponectin and its receptors AdipoR1 and AdipoR2 in fresh human GCs by reverse transcriptase-polymerase chain reaction (RTPCR) and immunoblot, respectively. Measurement of P and E2 levels in the conditioned media by RLA, and determination of cell proliferation by tritied thymidine incorporation. Result(s): Human GCs express adiponectin receptors AdipoR1 and AdipoR2 but not adiponectin. In primary human GCs, adiponectin increases P and E-2 secretion in response to insulin-like growth factor I (IGF-I). This was associated with an increase in the p450 aromatase protein level but not those of p450scc, 3 beta HSD, or StAR. Adiponectin treatment does not affect IGF-I-induced cell proliferation and basal steroidogenesis (no IGF-I or FSH stimulation). Adiponectin rapidly stimulates MAPK ERK1/2 and p38 phosphorylation in primary human GCs. Conclusion(s): Adiponectin receptors AdipoR1 and AdipoR2, but not adiponectin, are present in human GCs. Adiponectin increases IGF-I-induced P and E-2 secretion in primary human GCs. (Fertil Steril(R) 2009;92:1988-96. (C)2009 by American Society for Reproductive Medicine.)