Lack of correlation between sex hormone binding globulin, adrenal and peripheral androgens in precocious adrenarche

Sex hormone binding globulin (SHBG) is a specific steroid-binding plasma glycoprotein regulated by several different factors. Sex steroids are currently considered to be the main physiological regulators of this protein. Testosterone (T) in adults seems to be the main hormone active in lowering SHBG. The role of dihydrotestosterone (DHT) in such regulation, particularly in the prepubertal age, is not well understood, and no data exist about the role of 3 alpha-androstanediol (3A alpha) and its glucuronide. In adulthood, in addition to T, 5-ene steroids seems to play a role in the regulation of SHBG plasma concentration. To assess the effect of adrenal and peripheral androgens in modulating SHBG levels in the prepubertal age, we studied subjects with precocious pubarche secondary to precocious adrenarche (PA). PA represents, in fact, a good model of study as it is characterized by an increased production and action of adrenal androgen in females under 8 yr of age and in males under 9. Sixty-five subjects (55 females and 10 males; chronologic age: 3.6 - 8.2 yr (6.9 +/- 1.3, SD); bone age: 3.6 - 11 yr (7.6 +/- 1.9); BMI 17.9 +/- 3 kg/m2) were studied. Fifteen age-matched normal children (BMI 15.2 +/- 0.8 kg/m2) were studied as controls. Androstenedione (A), dehydroepiandrosterone (DHA) and its sulphate (DHA-S), T, DHT, 3Ad and its glucuronide (3AG) and SHBG were evaluated in all subjects. In PA cases serum SHBG levels (50 +/- 27 nM) were significantly lower (p less than 0.05) with respect to normal prepubertal patients.(ABSTRACT TRUNCATED AT 250 WORDS)