RESUMOA hiperinsulinemia parece contribuir para o hiperandrogenismo por reduzir os níveis séricos tanto da SHBG quanto da IGFBP-1. Avaliamos os níveis de SHBG e IGFBP-1 e sua correlação com androgênios e insulina em 44 meninas selecionadas com pubarca precoce (PP) e 18 controles (C) pré-puberais (7,3±1,3 x 6,8±1,6 anos). Foram avaliados: o índice de massa corporal (IMC), a idade óssea (IO) e os níveis séricos de SHBG, IGFBP-1, insulina (I), glicose (G), testosterona (T), androstenediona (A), SDHEA e cortisol (F). Calculamos a relação glicose: insulina (G/I) no jejum como índice de resistência à insulina (RI). A IO foi maior na PP, mas o IMC foi semelhante aos C. Os níveis de SDHEA, T e A foram maiores, enquanto a SHBG e a IGFBP-1 foram menores na PP do que nos C. Na regressão simples, a SHBG mostrou correlação com IMC, F, SDHEA, T, I, G/I e IGFBP-1, enquanto a IGFBP-1 se correlacionou com IMC, I e a G/I. No modelo de regressão múltipla, tanto a SHBG quanto a IGFBP-1 correlacionaramse apenas com o IMC e a taxa G/I (r 2 =0,45; p<0,01 e r 2 =0,44; p<0,01, respectivamente). Nossos dados demonstram que o peso corporal e a insulina têm um papel sinérgico na regulação dos níveis da SHBG e da IGFBP-1, sugerindo que ambos podem ser marcadores sutis da RI na PP.
ABSTRACT Sex Hormone Binding Globulin and IGF-Binding-Protein 1: Markers of Insulin Resistance in Premature Pubarche?Hyperinsulinemia may contribute to hyperandrogenism because it reduces the levels of SHBG and IGFBP-1. In this study we determined serum levels of SHBG and IGFBP-1 and their association with androgen and insulin in 44 selected girls with premature pubarche (PP) and 18 prepubertal controls (C) (7.3±1.3 x 6.8±1.6years). The body mass index (BMI) and bone age (BA) were determined, as well as the serum levels of SHBG, IGFBP-1, insulin (I), glucose (G), testosterone (T), DHEAS, androstenedione (A), 17-hydroxyprogesterone (17OHP) and cortisol (F). Fasting glucose to insulin ratio (G/I) was calculated as an index of insulin resistance (IR). BA was higher in PP than in C, but BMI was similar in both groups. Serum levels of DHEAS, T and A were higher in PP than in C, whereas SHBG and IGFBP-1 were lower. SHBG was correlated with BMI, SDHEA, T, F, I, G/I and IGFBP-1; and IGFBP-1 was correlated with BMI, I and G/I ratio. In the multiple regression model, SHBG and IGFBP-1 were correlated only with BMI and G/I ratio (r 2 =0.45; p<0.01 and r 2 =0.44; p<0.01, respectively). The present data demonstrate that body weight and insulin have a synergic role in the regulation of serum SHBG and IGFBP-1 levels, suggesting that both could be tenuous markers of IR in PP.