Adrenal gland in experimental renal hypertension.

The effect of total adrenalectomy on the mechanisms of arterial pressure control was studied in uninephrectomized rats with and without renal artery stenosis (Goldblatt one-kidney model). Four groups of rats were prepared and maintained on high-salt intake (1% NaCl): uninephrectomized-KI; KI + adrenalectomy-KIAx; uninephrectomized with renal artery stenosis-GI; and GI with adrenalectomy-GIAx. Over 3 wk blood pressure rose significantly in both GI and GIAx but the degree of increase in GI was greater. Hyponatremia, hyperkalemia, and increased plasma urea nitrogen were observed in both KIAx and GIAx. Plasma renin concentration (PRC) and plasma renine activity (PRA) were markedly increased and plasma renin substrate (PRS) was decreased in both adrenalectomized groups. Infusion of saralasin resulted in significant and similar reductions in mean arterial pressure (MAP) in KIAx and GIAx, but had no effect on MAP in KI and GI. These results allow approximations of the contribution to total MAP of identifiable components, which are: the total adrenal component, the renin-angiotensin system component, which partially compensates for loss of the adrenal secretions, and the independent effect of the renal artery clip. Thus, a multifactorial analysis of GI hypertension is provided.