Circulation Research, Vol 49, 416-423, Copyright © 1981 by American Heart Association

ARTICLES

Ontogeny of blood pressure and the renin-angiotensin-aldosterone system. Sequential studies in the newborn lamb

TA Wilson, DL Kaiser, EM Wright Jr, MJ Peach and RM Carey

To test the hypothesis that the rise in arterial pressure occurring with maturation is due to an increase in the vascular responsiveness to angiotensin II, sequential cumulative doses of angiotensin II were infused intravenously into chronically catheterized newborn lambs maintained on a constant, weight-adjusted sodium intake from birth to 8 weeks of age. Basal mean arterial pressure correlated with both age and weight, but age was a stronger determinant of mean arterial pressure than was weight. No change in the mean arterial pressure response to angiotensin II occurred with maturation. Basal plasma renin activity and plasma aldosterone concentrations were low and did not change significantly with age. Therefore, in the newborn lamb in the sodium replete state, age is a better determinant of arterial pressure than is weight. However, an age-related change in vasoconstrictor responsiveness to angiotensin II does not occur and, therefore, cannot account for the rise in arterial pressure that is observed with maturation.

This article has been cited by other articles:

				M. L Chappellaz and F. G Smith Dose-dependent systemic and renal haemodynamic effects of angiotensin II in conscious lambs: role of angiotensin AT1 and AT2 receptors Exp Physiol, November 1, 2005; 90(6): 837 - 845. [Abstract] [Full Text] [PDF]