The role of growth hormone in the pathogenesis of postmenopausal osteoporosis.

The secretory response of somatotropic hormone (STH) to arginine hydrochloride stimulation (0.5 g/kg) was studied in 13 postmenopausal women. Eight showed evidence of osteoporosis, based on clinical and morphoradiological data and on metacarpal cortical thickness measurement, and five had normal bone mass. In addition, the response to levodopa (500 mg) was determined in four of the osteoporotic patients. Baseline STH concentrations in the osteoporotic subjects did not differ from those in the nonosteoporotic group, but the latter showed a significant increase over the former at 45, 60, 90, and 120 minutes after stimulation. Similar findings were obtained with levodopa stimulation. Without necessarily implying a cause-effect relationship, our data appear to support the hypothesis that the poor secretory response of STH may be to some degree responsible for the osteopenia observed during the climateric.