Natriuretic Effect of Calcitonin in Man

Abstract

Porcine calcitonin was given to eight patients by continuous infusion for six to 39 days. Renal sodium and water excretion increased for 48 hours, and 0.5 to 1.6 kg of body weight was lost. A new steady state followed, with body weight below, sodium excretion the same as, and aldosterone secretion rate and plasma renin activity above, control levels. After the calcitonin infusion was stopped, there was sodium retention, and body weight returned to control values. Contamination or species difference as an explanation of these effects was unlikely because in short-term studies, porcine and synthetic human calcitonin had identical effects. The absence of a simultaneous increase in the excretion of cyclic adenosine-3′,5′-monophosphate suggests that the increase of sodium excretion was not due to a secondary increase of parathyroid-hormone secretion. Plasma calcitonin concentration achieved during continuous infusion suggests that calcitonin in physiologic amounts causes sufficient sodium and water loss to strain volume homeostasis.