Gonadal
steroids are believed to influence
glucose metabolism, oestrogens inducing an improvement and
androgens or
progestins a deterioration. At baseline and after 3 months of ovarian suppression with a gonadotrophin-releasing
hormone analogue (GnRHa:
goserelin depot 3.75 mg/28 days),
glucose metabolism was evaluated in eight lean women affected by ovarian
hyperandrogenism (PCOS) and six age-weight-matched non-hyperandrogenic women (controls) by using both an oral
glucose tolerance test (75 g; OGTT) and the minimal model method. The latter method allows calculation of peripheral
insulin sensitivity (Si) and
glucose dependent
glucose utilization (Sg). In PCOS, higher fasting concentrations (P < 0.05) of
insulin and
C-peptide, and lower Sg (P < 0.05) and Si (P < 0.01) were found. GnRHa did not significantly modify
glucose metabolism of controls, while in women with PCOS it decreased fasting
glucose (P < 0.05) and significantly increased Si (P < 0.03) up to control values. The present data indicate that strong suppression of ovarian activity improves Si in lean women with PCOS, while it is without relevant effects on
glucose metabolism of non-hyperandrogenic women.