PRELIMINARY FINDINGS ON THE EFFECTS OF SEX-HORMONES ON BONE METABOLISM IN ANOREXIA-NERVOSA

We performed tetracycline double-labeled bone biopsies and serial bone densitometry on four patients with anorexia nervosa to determine the effects of various conditions of sex hormone replacement and body weig ht status. We found negligible bone mineral apposition rate in two pat ients with anorexia nervosa who were taking estrogen and progestin pil ls while weighing only 79% of normal. However, bone mineral apposition rate was normal in two patients with anorexia nervosa who took no sex hormones and remained amenorrheic while weighing 87% of normal. Histo morphometric analysis revealed a decrease in intracortical trabecular area by 57% and an increase in active osteoblastic surface area by 300 %, comparing the subjects who were taking hormone replacement to those who were not. There was no direct evidence of increased resorption in any subject. Six months after biopsy, the two subjects taking sex hor mones decreased lumbar bone mineral density by 1.9%, while the two tak ing no sex hormones remained amenorrheic, but increased bone mineral d ensity by 1.3%. Therefore, we propose that sex hormone therapy in the presence of persistently low body weight might be of limited benefit f or bone mineral apposition and density.