The effects of catecholamines on the distribution of 14C-cholesterol in dogs.

Abstract

AbstractFifteen adult male pure bred Beagle dogs were given 4‐14C‐cholesterol and a subsequent 18 day period was permitted to elapse for equilibration of the14C‐cholesterol between blood and tissue compartments. Peanut oil, epinephrine in oil or norepinephrine in oil was administered by daily subcutaneous injections over a period of 63 to 81 days. Epinephrine but not norepinephrine resulted in sustained increases in plasma cholesterol concentrations. The half‐life of14C‐cholesterol in plasma was 19 days in control dogs, 18 days in catecholamine treated dogs. The slope of the decline in the specific radioactivity of plasma cholesterol did not change during epinephrine administration, suggesting an influx into plasma of endogenous cholesterol. Specific radioactivity of thoracic aorta cholesterol was fourfold greater than that of plasma cholesterol in control dogs at the end of the experiment and 1.3‐fold greater than the specific radioactivity of cholesterol in the lower aortic segments. Treatment with epinephrine decreased the specific radioactivity cholesterol in all segments of the aorta and resulted in cholesterol specific radioactivity from thoracic aorta which was less than that of cholesterol from the lower aortic segments. Norepinephrine treatment resulted in decreases in the specific radioactivity of cholesterol from the thoracic and abdominal aortic segments but the changes were smaller than those observed in epinephrine treated dogs.