Effect of a single dose of nicotinic acid on plasma lipids in patients with hyperlipoproteinemia.

Abstract

Abstract Eleven patients with uncomplicated ischemic cardiovascular diseases and moderate hyperlipoproteinemia were studied for 6 hours after the administration of one gram of placebo and two days later one gram of nicotinic acid.Plasma levels of free fatty acids were significantly depressed by nicotinic acid as compared to the control study during the first three hours after administration. Then, however, there was a pronounced rebound of FFA. The concentration of glycerol in plasma followed the same pattern as the free fatty acids.The values for cholesterol in plasma remained unchanged during the six‐hour period in both the placebo and the nicotinic acid study. While the level of triglycerides as well was unchanged in the placebo study, the concentration of triglycerides decreased significantly 4 and 6 hours after the administration of nicotinic acid.The concentration of blood glucose was not significantly different in the two groups during the study.The concentration of free nicotinic acid in plasma reached a peak value 30 to 60 minutes after nicotinic acid was taken by mouth. At 5–6 hours the level had returned to pretreatment values. The values for the plasma levels of free nicotinic acid and free fatty acids indicated that a concentration of nicotinic acid above 1 μg/ml plasma is needed to maintain low free fatty acid levels.The interrelation between free fatty acids, triglycerides and cholesterol in plasma is discussed. The results from these studies are compatible with the hypothesis that acute inhibition of FFA mobilization reduces the concentration of plasma triglycerides but not plasma cholesterol. They do not explain the mechanism behind the cholesterol‐lowering effect of nicotinic acid seen after chronic administration.