Beta blockers and their effects on lipoproteins, phospholipids, apoproteins A and B, in whole plasma and the different fractions.

Plasma levels of cholesterol (C), triglycerides (TG), phospholipids (PL) (in total plasma, very low density [VLDL], low density (LDL), and high density [HDL] lipoproteins) and of two apolipoproteins (apo-B and apo-A) were studied in 13 hyperlipidemic patients suffering from hypertension and/or stable angina and treated by metoprolol or propranolol. Propranolol reduced the low density and high density lipoprotein phospholipids by 26% and 11%, respectively, and increased the very low density phospholipids by 24%. Metoprolol had only a transient effect on high density lipoprotein phospholipids. VLDL apolipoprotein-B was markedly increased by propranolol (67%), whereas apolipoprotein-A was slightly (8%) increased during metoprolol treatment. The reduced low density lipoprotein phospholipids and the increased high density lipoprotein apo-A correlated with the plasma concentration of propranolol and metoprolol, respectively. These results suggest that the comparative effects of beta-adrenoreceptor blocking agents on lipoprotein metabolism should be considered in their long-term use in patients with risk factors for hypertension and myocardial infarction.