Cardiovascular Responses of Calcitonin in Rats

Abstract

Isolated hearts were perfused usmg Lanr,endorfT technique and examined for basal activities as well as their responses to isoproterenol infusion, regarding heart rate, peak developed tension, time to peak tension, half relaxation time as well as coronary flow per minute. The results of this study revealed that single administration of calcitonin resulted in a sig11ificant hypocalcemic, hypophosphatemic responses as well as significant increase in HDL-cholesterol. On the other hand, isolated hearts revealed that, the increase in absolute basal peak developed tension as well as absolute corom. ty flow was insignificant compared to their matching controls. Administration of calcitonin for two weeks resulted in a significant hypocalcemia associated with hypocholesterolemia. These changes were accompanied by an elevation of mean arteriai blood pressure. Although, the obtained tachycardia was insignificant, yet, the arterial blood pressure - heart rate product was significantly elevated. Isolated hearts, revealed a significant elevation of basal heart rate accompanied by insignificant increase in absolute basal peak developed tension.