[The effect of parathormone on the reactivity of the cardiovascular system to angiotensin-2 in normotensive and spontaneously hypertensive rats].

The effect of parathyroid hormone (2 units/100 g) on hemodynamic response to various doses of i.v. angiotensin-2 (16 ng/100 g; 20 ng/100 g; 24 ng/100 g) was studied in normotensive and spontaneously hypertensive rats. The effect involved a decrease of the minute blood volume, stroke volume, and an increase of total peripheral resistance in normotensive rats. Parathyroid hormone decreased total peripheral resistance and increased the minute blood volume and the heart rate in spontaneously hypertensive rats. Angiotensin-2 raised the arterial pressure in normotensive rats. In presence of parathyroid hormone, the angiotensin-2 pressor effect was quite obvious in normotensive rats whereas in spontaneously hypertensive rats angiotensin-2 effect caused the greatest rise of arterial pressure as a result of a considerable dose-dependent rise of total peripheral resistance, the cardiac output showing a tendency towards a reduction.