[Antihypertensive action of elcatonin]

Subcutaneous injections of elcatonin, a synthetic analogue of eel calcitonin, lowered the blood pressure in DOCA/saline-hypertensive and spontaneously hypertensive rats (SHR), but not in normotensive Wistar rats. The hypotensive effect was more prominent in the DOCA hypertensive rats. Daily injections of elcatonin (10-30 U/kg/day for 21 days) resulted in maximum hypotension on the 4th day in DOCA hypertensive rats and on the 14th day in SHR, and the reduced level of blood pressure was maintained. After the cessation of elcatonin injections, the pressure started to elevate gradually towards the control level. In normotensive rats, elcatonin did not significantly alter the blood pressure for 6 weeks. Daily injections of elcatonin significantly prevented the development of DOCA-induced hypertension and spontaneously-occurring hypertension. Elcatonin-induced hypotension did not differ in the control and parathyroidectomized DOCA hypertensive rats. Elcatonin did not alter the pressor response to noradrenaline, vasopressin and angiotensin II nor the depressor response to isoproterenol, acetylcholine and histamine in DOCA hypertensive rats. It is concluded that the antihypertensive effect of elcatonin is not associated with the release of parathyroid hormone nor with the blockade of alpha, beta, angiotensin II and vasopressin receptors.