Objective: To study expression of insulin receptor substrate 1 (IRS-1) and phosphorylation of tyrosine in adipose tissue of polycystic ovary syndrome (PCOS) to approach the mechanism of insulin resistance (IR) in PCOS at tissue and cellular level.
Methods: IRS-1 expression and tyrosine phosphorylation of adipose tissue were studied with immunoprecipitation, Western-blot and ECL immunoblotting.
Results: The differences of IRS-1 expression in adipose tissue among the obese PCOS group (82 +/- 15)%, the non-obese PCOS group (79 +/- 18)%, the obese control group (75 +/- 19)% and the non obese control group (70 +/- 19)% were not significant (P > 0.05). IRS-1 tyrosine phosphorylation in adipose tissue in the obese PCOS group [(52 +/- 23)%, P < 0.001], the obese control group [(45 +/- 22)%, P < 0.01] and non-obese PCOS group [(70 +/- 25)%, P < 0.05] were markedly lower than that in the non-obese control group (88 +/- 12)%. The obese control group had more reduction than non-obese control group (P < 0.05). The differences between the obese PCOS group and the obese control group or the two PCOS groups were not significant (P > 0.05).
Conclusion: IRS-1 tyrosine phosphorylation in adipose tissue in the two PCOS groups decreased markedly than in the non-obese control group. It might be involved in the disorder of insulin-signaling transduction downstream of insulin receptor and the occurrence of IR.