Enhancement of exogenous triglyceride removal following calcium channel blockade

Adrenergic regulation of lipid metabolism is mediated by various intracellular messengers, including calcium ions. Little is known about the role of calcium in the catabolism of triglyceride-rich lipoproteins. Aim of this study was to investigate whether blockade of calcium influx across the cell membrane influences lipid metabolism in man. The calcium entry blocker nitrendipine was administered to 10 hypertensive, normolipidemic subjects for eight weeks at the dose of 10 mg b.i.d. An enhancement in plasma clearance of triglyceride was observed after nitrendipine administration: fractional removal rate of the triglyceride emulsion Intralipid increased by 22% (from 3.13 +/- 1.1 after placebo to 3.81 +/- 1.4% min after nitrendipine, p less than 0.03). Fasting serum triglyceride was not shifted (83 +/- 57 vs 84 +/- 37 mg/dl). Total serum cholesterol and cholesterol in high density lipoproteins were also unchanged during the study. No evidence of change in insulin response was detected. It is hypothesized that calcium plays a role in the modulation of lipoprotein lipase, the enzyme mainly responsible of the removal of exogenous triglyceride from plasma. Alternatively, the increase in the clearance rate of the triglyceride emulsion might be explained by the vasodilating activity of nitrendipine.