Acanthosis nigricans (AN), a hyperplastic skin lesion found in 7% of school children, is associated with insulin resistance and hyperinsulinemia. In adults, insulin resistance is associated with low SHBG. The latter has been shown to be a risk factor for future development of NIDDM. The purpose of the present study was to evaluate if the degree of insulin resistance/hyperinsulinemia is associated with low SHBG and IGF-BP1 in children with acanthosis nigricans.

Nine girls (5 Black, 3 White, 1 Biracial), age 11.7 ± 2.6 yrs, body mass index (BMI) 29.8 ± 6.1 kg/m2 were studied. The subjects underwent a 3-hr (80 mu/m2/min) hyperinsulinemic- euglycemic clamp to determine in vivo insulin action, and a 2-hour hyperglycemic clamp (225 mg/dl) to assess first and second phase insulin secretion. Insulin-mediated glucose disposal (Rd) was calculated over the last 30 min of the hyperinsulinemic clamp. Results are (mean ± SEM) Table

Table 1 No caption available.
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Rd correlated with IGF-BP1 (R=0.70, P=0.017) and SHBG (R=0.67, P=0.04). Fasting insulin, first-phase insulin and second-phase insulin did not correlate significantly with SHBG or IGF-BP1. In summary, our results demonstrate that insulin resistance correlates with low sex hormone binding globulin and low IGF-BP1 in children with AN while degree of insulinemia does not show any significant correlation. A potential explanation for the lack of correlation of insulinemia with SHBG and IGF-BP1 is varying degrees of pancreatic B-cell function in these children. Additional studies of children without acanthosis nigricans are underway to further elucidate the natural relationships of SHBG and IGF-BP1 to insulin action/insulinemia in children.