Association between sympathetic activity and the atherogenic serum cholesterol fraction

A possible modulating influence of noradrenergic activity on serum lipoproteins was assessed under placebo conditions and following 4 weeks of sympathetic neurone blockade with debrisoquine in 9 normal subjects, 11 patients with mild essential hypertension, 9 normotensive, and 9 hypertensive hemodialysis patients. Plasma norepinephrine (NE) did not differ significantly among groups on placebo and was consistently reduced (P less than 0.05-0.001) by sympathetic blockade. The latter also decreased (P less than 0.05-0.001) plasma total cholesterol (C) as well as low and very low density lipoprotein cholesterol (LDL + VLDL-C) in the three patient groups. In the two dialysis groups, basal levels of plasma triglycerides (Tg) were increased and high density lipoprotein cholesterol (HDL-C) was diminished (P less than 0.01-0.001); sympathetic blockade lowered Tg and raised HDL-C (P less than 0.01-0.001). In normal subjects, sympathetic blockade did not significantly modify plasma lipoproteins. In the three patient groups, significant correlations (r = 0.62 - 0.88; P less than 0.05 - less than 0.001) existed between (a) basal plasma NE and total C or LDL + VLDL-C and (b) debrisoquine-induced changes in NE and changes in total LDL + VLDL-C. These findings suggest that in essential hypertension as well as in hemodialysis patients, the atherogenic C fraction, represented by LDL + VLDL-C, may be modulated by the noradrenergic activity.