Functional ovarian hyperandrogenism, a variant of polycystic ovary syndrome, is often associated with hyperinsulinism and dyslipidemia. The mechanisms interlinking this triad are poorly understood; both hyperandrogenism and hyperinsulinism have been proposed as factors involved in the pathogenesis of the dyslipidemia. Precocious pubarche (PP) in girls is a risk factor for subsequent anovulation, ovarian and adrenal hyperandrogenism, hyperinsulinism and dyslipidemia. Flutamide, a nonsteroidal antiandrogen, is known to be effective in reducing hirsutism in patients with ovarian hyperandrogenism. However, the effects of flutamide on the endocrine-metabolic correlates of hyperandrogenism are uncertain. We assessed the effects of low dose flutamide treatment (250 mg daily for 18 months) on hormonal and metabolic variables in 18 nonobese adolescent girls (age, 16.8 +/- 0.3 yr) with functional ovarian hyperandrogenism (diagnosis by GnRH agonist test) after PP. Flutamide treatment was accompanied by a marked decrease in the hirsutism score, free androgen index, and testosterone, androstenedione, and dehydroepiandrosterone levels and by an increase in sex hormone-binding globulin concentrations. However, there were no substantial changes in the pattern of menstrual cycles, gonadotropin, estradiol, or dehydroepiandrosterone sulfate concentrations, and there was no detectable effect on the 17-hydroxyprogesterone response to GnRH agonist. Serum triglycerides, total cholesterol, and low-density lipoprotein cholesterol levels decreased markedly during flutamide therapy, whereas high-density lipoprotein cholesterol, fasting glycemia/insulinemia, and the insulin response to a glucose load remained unchanged. Flutamide was well tolerated. In conclusion, low dose flutamide treatment was found to be an effective and safe approach to reduce hirsutism and circulating androgen, low-density lipoprotein cholesterol, and triglyceride levels in girls with functional ovarian hyperandrogenism after PP. However, flutamide failed to increase high-density lipoprotein cholesterol levels or decrease hyperinsulinemia, i.e. to affect two major risk factors for subsequent cardiovascular disease.