Racial differences in the correlation between gonadal androgens and serum insulin levels.

OBJECTIVE: We previously demonstrated a direct correlation between serum insulin levels and gonadal androgens (testosterone and androstenedione) in a group of obese hyperandrogenic predominantly black women. Subsequent work by others in predominantly white women showed conflicting results. To examine these potentially important racial differences further, 14 premenopausal females from each ethnic group, of similar age, BMI, and waist-to-hip ratio, were studied. RESEARCH DESIGN AND METHODS: We measured baseline gonadal androgens, dehydroepiandrosterone (DHEA), dehydroepiandrosterone sulfate (DHEAS), and leutinizing hormone (LH)/follicle-stimulating hormone ratio. Serum glucose, insulin, and C-peptide were measured at baseline and during a 2-h oral glucose tolerance test (area under the curve [AUC]). Insulin sensitivity was measured by glucose decrement during the first 15 min of an intravenous insulin tolerance test. RESULTS: Simple correlation analysis revealed a significant direct correlation in blacks (but not whites) between gonadal androgens and AUC for glucose, insulin, and C-peptide. Race-by-covariate interaction models reinforced the simple correlation finding. Cholesterol level was also correlated to all androgens in blacks, but not in whites. We also found that whites had higher serum triglycerides and greater AUC glucose than blacks. CONCLUSIONS: We conclude that there is a significant direct correlation between gonadal androgens and stimulated glucose, insulin, and C-peptide in blacks but not in whites. Thus, the previously reported direct correlation between gonadal hyperandrogenism and hyperinsulinemia may be a race-dependent phenomenon, hitherto an unreported observation. The implications of these findings are discussed.

Effect of calcitriol and pamidronate in multiple myeloma.

Addition of bisphosphonates to standard treatment of multiple myeloma (MM) decreases bone pain and skeletal events without influencing bone healing. Calcitriol, besides its established effects on bone remodeling and calcium metabolism, has both immunoregulatory and cell differentiating effects in vitro and in vivo. Moreover, low serum calcitriol has been reported in MM. We tested the effects of supportive treatment with calcitriol and pamidronate on bone disease in two stage-III-B MM patients with diffuse bone involvement, normal serum calcium, and low serum calcitriol. Complete blood counts, serum calcium, creatinine, quantitative serum and urine immunoglobulins, and biochemical indices of bone turnover, serum calcidiol, calcitriol, parathyroid hormone, skeletal radiographs, and bone mineral density by dual x-ray absorbtiometry were measured every 1-6 months for 16 months in the first patient and 7 months in the second patient. Both patients showed a dramatic improvement of MM activity and in bone disease documented by serial radiographs in the first patient and by increased bone mineral density (approximately 15%) in the second. The reduced serum calcitriol in both patients and the elevated parathyroid hormone observed in the first patient before treatment returned to normal. Supportive treatment with pamidronate does not induce bone healing in MM. Therefore, the results observed with the addition of calcitriol suggest that this hormone may have contributed to the apparent arrest of the progression of MM and caused stimulation of bone healing.

Pretreatment with propylthiouracil but not methimazole reduces the therapeutic efficacy of iodine-131 in hyperthyroidism.

Ninety-three hyperthyroid patients were treated with 1 dose of iodine-131 (131I) during the past 10 years. Thirty-three were pretreated with propylthiouracil (PTU), 22 with methimazole (MMI), and 38 received no antithyroid drugs (ATD). ATD were discontinued 5-55 days before 131I therapy in three fourths of the cases and more than 4 months before therapy in one fourth of the cases. The frequency of cures in the 3 groups, 6-8 months after radioiodine therapy, was retrospectively studied. The cure rate among those who discontinued PTU for 5-55 days before 131I was significantly reduced (24%), compared with those who discontinued MMI for the same duration (61%) or those who received no ATD (66%). When PTU was discontinued for more than 4 months, the cure rate was similar to those who received no ATD. It is concluded that if ATD are used as initial therapy for hyperthyroidism, then PTU (but not MMI) may reduce the therapeutic efficacy of subsequent 131I. The reduction in cure rate was observed even when PTU was discontinued for as long as 55 days before 131I therapy. To our knowledge, this is the first report to compare, in one study, the effects of pretreatment with PTU and MMI on 131I therapy.