GROWTH-HORMONE, INSULIN-LIKE GROWTH-FACTOR-I AXIS, AND INSULIN-SECRETION IN HYPERANDROGENIC ADOLESCENTS

Objective: To assess GH and insulin-like growth factor I (IGF-I) axis variability in hyperandrogenic adolescents with different sources of androgen excess and their relationship with insulin resistance. Design: Baseline IGF-I, insulin-like growth factor binding protein-1 (IGFBP-1), IGFBP-3, GH response to the exercise-propranolol test, and insulin responses to a standard oral glucose tolerance test were compared among patients with functional ovarian hyperandrogenism, hyperandrogenic nonfunctional ovarian hyperandrogenism patients, and age-matched controls. Setting: Outpatient clinic in a medical center. Patients: Twenty-one adolescents with ovarian (group A) and 17 with nonovarian (group B) hyperandrogenism, and 20 controls. Results: Serum IGF-I and poststimulated GH levels were similar among groups, whereas serum IGFBP-3 levels were significantly lower in group A than in controls. Mean serum insulin levels were significantly higher in patients than in controls, whereas 24% of patients had abnormal insulin responses to glucose and/or insulin sensitivity indexes. Serum IGFBP-3 levels correlated negatively with the free androgen index (free androgen index = T/sex hormone-binding globulin [SHBG] x 100), whereas mean serum insulin levels correlated positively with the free androgen index and negatively with SHBG levels in all subjects. Conclusions: Hyperinsulinemia is common in hyperandrogenic adolescents and correlates with the degree of hyperandrogenism and not with the androgen source. Hyperinsulinemia and decreased IGFBP-3 levels may enhance IGF-I bioavailability, which in turn may both decrease SHBG levels and increase androgen production.