Lipid Composition of Human Red Blood Cells and White Blood Cell-Platelets with and without Administration of Nicotinic Acid

Five normal, healthy, men (age 33-42) served as experimental subjects. The subjects were on self-chosen diets and received a test-dose of buffered nicotinic acid (Nico-Span in capsule form) of 2 gm daily for three weeks, from the second through the fourth weeks, of the six and one-half week test period. About 30 ml of venous blood was obtained twice weekly from each subject, after an overnight fast of at least 12 hours. Each subject collected a 24-hour urine sample of the day prior to the blood sampling and also kept a record of food eaten. The blood was separated into serum, red cell, and white cell-platelet samples. Total lipids were extracted from red cells and white cell-platelets. Chemical determinations of total lipids, free and total cholesterol, and lipid phosphorus were made on these extracts. Concentrations of cholesterol ester, and phospholipids were calculated and triglyceride plus free fatty acid were found by difference. In red cells, on the average, total lipids were increased by 34 mg per 100 ml of red cells during treatment and after discontinuation of the treatment were further increased by 3 mg. Cholesterol esters were decreased by 1 per cent and increased by less than 1 per cent during and after treatment, respectively. Free cholesterol values dropped in the treatment period and then rose in the post-treatment period by small amounts. Triglyceride plus free fatty acids and phospholipid values showed a rise and then drop during and after the treatment respectively, but these changes were slight. For white cell-platelets, total lipids, on the average, showed a rise of 132 g and a further rise of 90 mg per 100 gm of white cell-platelets during and after the treatment period, respectively. Cholesterol ester showed a drop and a rise of 1 per cent both during and after the treatment; whereas free cholesterol values showed the reverse, an increase first and then a drop of 1 per cent both in treatment and post-treatment period. Mean triglyceride plus free fatty acids values dropped by 1 per cent during treatment and remained the same when the treatment was started, but were increased by 1 per cent when the treatment was discontinued. It was concluded that total lipid and its components in red cells and white cell-platelets were not affected to a great degree when 2 gm doses of nicotinic acid were administered for a short period of time. Further work using a greater number of subjects, with a longer study period and increased doses of nicotinic acid is recommended to clearly define the relationship of administration of nicotinic acid and lipid composition of red ells and white cell-platelets