L. Ibanez et al., GROWTH-HORMONE, INSULIN-LIKE GROWTH-FACTOR-I AXIS, AND INSULIN-SECRETION IN HYPERANDROGENIC ADOLESCENTS, Fertility and sterility, 64(6), 1995, pp. 1113-1119
Objective: To assess GH and insulin-like growth factor I (IGF-I) axis
variability in hyperandrogenic adolescents with different sources of a
ndrogen 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 amon
g patients with functional ovarian hyperandrogenism, hyperandrogenic n
onfunctional ovarian hyperandrogenism patients, and age-matched contro
ls. Setting: Outpatient clinic in a medical center. Patients: Twenty-o
ne adolescents with ovarian (group A) and 17 with nonovarian (group B)
hyperandrogenism, and 20 controls. Results: Serum IGF-I and poststimu
lated GH levels were similar among groups, whereas serum IGFBP-3 level
s were significantly lower in group A than in controls. Mean serum ins
ulin levels were significantly higher in patients than in controls, wh
ereas 24% of patients had abnormal insulin responses to glucose and/or
insulin sensitivity indexes. Serum IGFBP-3 levels correlated negative
ly with the free androgen index (free androgen index = T/sex hormone-b
inding globulin [SHBG] x 100), whereas mean serum insulin levels corre
lated positively with the free androgen index and negatively with SHBG
levels in all subjects. Conclusions: Hyperinsulinemia is common in hy
perandrogenic adolescents and correlates with the degree of hyperandro
genism and not with the androgen source. Hyperinsulinemia and decrease
d IGFBP-3 levels may enhance IGF-I bioavailability, which in turn may
both decrease SHBG levels and increase androgen production.