Plasma lipids and urinary excretion of catecholamines in man during experimentally induced emotional stress, and their modification by nicotinic acid.

33 male volunteers were studied in the morning after fasting overnight. 11 (the control group) were allowed to sit comfortably for three consecutive 2-hr periods, no stressors or treatment being introduced. The remaining 22 were divided into two groups, each being exposed to standardized, emotional stressors during the second of the three 2-hr periods. The subjects in one of these groups were each given a total dose of 3 g of nicotinic acid during the first 3 hr of the experiment, whereas the other group received no treatment. Stress was accompanied and followed by increased levels of free fatty acids and triglycerides in arterial plasma, by an increase in catecholamine excretion, and a rise in heart rate and systolic and diastolic blood pressure. No such increases were seen in the control group. The stress-induced rise in free fatty acids was inhibited by nicotinic acid, and the triglyceride rise was turned into a fall. The stressor-induced increase in catecholamine excretion was not significantly affected by nicotinic acid, neither were the increases in heart rate and blood pressure. The hypothesis is discussed, from a qualitative as well as a quantitative viewpoint, that there is a direct relationship between the increased concentration of free fatty acids accompanying emotional stress in man and the eventual development of the stress hyperlipoproteinemia.