Circulating plasma leptin and IGF-1 levels in girls with premature adrenarche: Potential implications of a preliminary study

Premature adrenarche is a condition characterized by precocious development of pubic and/or axillary hair, due to early onset of adrenal androgen secr etion. Girls with premature adrenarche may later develop menstrual irregula rities, hyperandrogenism, and the classic polycystic ovary syndrome. As lep tin is thought to modulate the onset of pubertal development, we measured p lasma leptin levels in 7 girls with premature adrenarche, and 8 age-matched comparison girls. Because leptin, the hypothalamic-pituitary-adrenal (HPA) , the hypothalamic-pituitary-gonadal axes are functionally interrelated, we also determined salivary and plasma cortisol, dehydroepiandrosterone (DHEA ), DHEA-sulfate, androstenedione, estradiol, and estrone. Finally, since IG F-I may play a role in adrenocortical function, we determined plasma levels of IGF-1, and IGF-BP1. Plasma was collected by an intravenous catheter at times 0, 20, and 40 min, starting at 1.30 p.m, Girls with premature adrenar che had a higher body mass index (BMI) and an over two-fold elevation of th eir plasma leptin than comparison girls. This group also had elevated level s of salivary and plasma cortisol, and increased levels of DHEA, DHEA-S, an drostenedione, estradiol and estrone. Plasma IGF-1 and the ratio of IGF-1/I GF-BP1 were elevated. We propose that girls with premature adrenarche may r epresent an overlapping group characterized by both features of increased a diposity and HPA axis activity, which together, and depending on the geneti c/constitutional background of the individual, may account for the developm ent of adrenal hyperandrogenism, and, later, the polycystic ovary syndrome.