The aim of this study was to describe the insulin profile and to determine the relationship with hyperandrogenism in the premature pubarche (PP). Twenty-three girls with PP due to premature adrenarche and 5 normal prepubertal control (C) girls were studied (7.3 ± 1.1 x 7.1 ± 1.8 years). The fasting levels of dehydroepiandrosterone sulfate (SDHEA), testosterone (T) and sex hormone binding globulin (SHBG) were measured. The body mass index (BMI) and the free androgen index (FAl) were calculated. The oral glucose tolerance test was performed; the fasting insulin (I) to glucose (G) ratio (FIGR = I/G) and the areas under the curve for G (AUCG) and I (AUCI) were calculated. A FIGR > 22 was suggestive of I resistance (IR). The BMI was higher in PP than in C (18.8 ± 3.0 x 15.5 ± 1.6, p = 0.03). Plasma levels of SDHEA (71.7 ± 40.6 x 34.2 ± 6.9µg/dl, p = 0.02), T (0.41 ± 0.4 x 0.17 ± 0.1nmol/L, p = 0,02) and FAl (0.73 ± 0.7 x 0.17 ± 0.04, p = 0.001) were higher in PP than in C, but SHBG levels (63.7 ± 23.1 x 110.2 ± 23.9nmol/L, p = 0.0006) were lower. The FIGR showed IR in 44% of patients, but the G, I, AUGC, AUIC and FIGR were similar in both groups. A negative correlation between SDHEA and I (r = -0.43, p = 0.04) and between SHBG and BMI (r = -0.74, p = 0.0001) and AUIC (r = -0.36, p = 0.09) were observed in PP. The AUIC showed a positive correlation with BMI (r = 0.56, p = 0.006) and FIGR (r = 0.86, p = 0.0001). Adrenal hyperandrogenism may not have adverse effects on I sensitivity at childhood, expressed here by the negative correlation between SDHEA and I, in girls with PP. But presence of the FIGR suggestive of IR was so common, that the exact relationship between the levels of adrenal androgens and I sensitivity remains unclear.
Insulin resistance; Adrenal hyperandrogenism; Premature pubarche
