The present double-blind placebo-controlled cross-over study was designed to evaluate the renin-angiotensin-aldosterone system behavior after a short-term infusion of a pharmacological dose (100 MRC U) of salmon calcitonin. Overall, a significant increase in plasma renin activity, aldosterone and serum angiotensin-converting enzyme was seen throughout. This effect may be, at least in part, due to the renal loss in sodium and calcium ions, while the increased kaliuresis could be interpreted as a consequence of the stimulation of aldosterone release.