INOTROPIC EFFECTS OF CALCITONIN IN MAN

Abstract

The hemodynamic response of 10 normal subjects to the i.v. administration of 160 MRCU [mouse radius calcifying units] of calcitonin in 60 min, was studied by serial measurement of the systolic time intervals. The analysis of results pointed out a minor inotropic effect starting from the 10th min from the beginning of the infusion. Small but significant decrements (P < 0.01) in the duration of the pre-ejection phase of the isovolumetric contraction time, and a significant increase (P < 0.01) in the LVET/PEP ratio, were noted. A negative chronotropic effect (P < 0.05) was noted starting from the 30th min. The mechanism by which calcitonin can modify the myocardial inotropism in the normal subject is unknown, but could be related to the interference of this hormone on the endocellular movements of Ca, and on the cellular levels of cyclic AMP.