Catecholamine Metabolism in Hypertensive Rats

Abstract

The possible role of catecholamines in two forms of experimental hypertension in rats was investigated further. Inbred, spontaneously hypertensive (SH) Wistar rats had unchanged endogenous levels of norepinephrine (NE) in the three tissues studied, and a significantly ( P <0.05) decreased rate of NE synthesis ( 14 C-tyrosine technique) in heart and brainstem but not in gut, in comparison to normotensive Wistar rats. Also, the levels of free fatty acids (FFA) and major urinary catecholamine metabolites in plasma revealed no evidence of increased catecholamine turnover or release. Sprague-Dawley rats rendered hypertensive by treatment with desoxycorticosterone acetate and 1% salt had decreased cardiac NE concentration and increased cardiac NE turnover ( 3 H-NE technique) and cardiomegaly, confirming the work of others. However, urinary normetanephrine and plasma FFA did not differ from those in normal rats. These and other results fail to support but do not completely exclude a primary role for catecholamines in either type of hypertension.