Effects of calcium antagonists and adrenergic antihypertensive drugs on plasma lipids and cellular cholesterol metabolism.
Calcium antagonists and antihypertensive alpha-adrenergic and beta-adrenergic drugs may cause changes in plasma lipoprotein levels. Different mechanisms by which these antihypertensive agents effect cellular lipid metabolism have been proposed. The activity of lipoprotein lipase that determines the catabolism of very low density lipoproteins (VLDL) is decreased by the beta-blocker propranolol and increased by alpha 1-antagonists. The plasma cholesterol or low density lipoprotein (LDL) level is inversely associated with the number of LDL receptors. Catecholamines suppress the LDL receptor activity, thus leading to an increase in plasma cholesterol concentration. The calcium antagonist verapamil and the beta-blocker propranolol may increase LDL receptor activity either per se or by its antagonizing effect on the catecholamine action. The metabolism of high density lipoproteins (HDL) may be affected directly by catecholamines, which might increase HDL binding activity, thereby enhancing efflux of cholesterol from cells. Catecholamines inhibit cholesterol biosynthesis in extrahepatic cells. The effects are mediated by alpha 2- and beta 2-adrenergic receptors. Accordingly, the alpha 2-agonists clonidine and alpha-methyldopa mimicked and propranolol opposed the catecholamine action. In contrast, the alpha 1 antagonists indoramin, prazosin, and urapidil had no effect on cholesterol synthesis. The results provide evidence that calcium antagonists and various antihypertensive drugs, depending upon their action on beta- or alpha-adrenergic receptors, affect lipid metabolism differently. The metabolic effect may play a role in atherogenesis and may be of clinical importance when antihypertensive treatment is considered.
Krone
W
W
Medizinische Kerklinik und Poliklinik, Universitäts-Krankenhaus Eppendorf, Hamburg, F.R.G.
Müller-Wieland
D
D
Nägele
H
H
Behnke
B
B
Greten
H
H
D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology; D000319:Adrenergic beta-Antagonists / Q000494:pharmacology; D000959:Antihypertensive Agents / Q000494:pharmacology*; D002121:Calcium Channel Blockers / Q000494:pharmacology*; D002784:Cholesterol / Q000378:metabolism*; D008078:Cholesterol, LDL / Q000378:metabolism; D006801:Humans; D008055:Lipids / Q000097:blood*; D008075:Lipoproteins, HDL / Q000378:metabolism; D008079:Lipoproteins, VLDL / Q000378:metabolism; D008099:Liver / Q000378:metabolism
D000317:Adrenergic alpha-Antagonists; D000319:Adrenergic beta-Antagonists; D000959:Antihypertensive Agents; D002121:Calcium Channel Blockers; D008078:Cholesterol, LDL; D008055:Lipids; D008075:Lipoproteins, HDL; D008079:Lipoproteins, VLDL; D002784:Cholesterol