Calcitonin and the calcium-regulating hormones in postmenopausal women: effect of oestrogens.

In man, the major function of calcitonin appears to be prevention of excessive or unwanted bone resorption. There is a striking sex difference in circulating levels, with a relative deficiency in women. Calcitonin secretion in young adults is increased by oestrogens and therefore long periods of oestrogen lack, such as after the menopause, may be associated with a more pronounced calcitonin deficiency. This exaggerated deficiency could be an important factor in the pathogenesis of postmenopausal bone loss, especially since the latter may be due to excessive bone resorption. In a study of the effects of oestrogen treatment on circulating levels of calcitonin, parathyroid hormone, and vitamin-D metabolites in postmenopausal women, the most striking change was a sharp rise in plasma-calcitonin. Oestrogens prevent postmenopausal bone loss, and it is suggested that this effect could be mediated, at least in part, through control of calcitonin secretion. Calcitonin may prove effective in the prevention of postmenopausal bone loss, and it is suggested that this effect could be mediated, at least in part, through control of calcitonin secretion. Calcitonin may prove effective in the prevention of postmenopausal bone loss. Its place in the treatment of postmenopausal osteoporosis warrants further evaluation.