The distribution of(14)C-labeled cholesterol in the dog: Effect of long-term epinephrine administration

A time course study of(14)C-cholesterol distribution in dogs was performed after the intravenous administration of 4-(14)C-cholesterol. Liver cholesterol attained isotopic equilibrium with plasma cholesterol within 24 hr after the administration of the labeled cholesterol. The tissue cholesterol pools of most organs attained isotopic equilibrium with plasma cholesterol between the second and ninth day after 4-(14)C-cholesterol had been given. Thoracic aorta cholesterol equilibrated most slowly with plasma cholesterol. Thirty-seven to 75 days after the(14)C-cholesterol had been given, the specific radioactivity of thoracic aorta cholesterol was 2 to 5 times greater than that of plasma cholesterol and 1.73 and 1.65 times greater than that of the abdominal and terminal aortic segments respectively. Adrenal gland cholesterol attained specific radioactivities greater than that of plasma cholesterol between the fourth and ninth day after 4-(14)C-cholesterol had been given, and this relationship was maintained over the 75-day period of observation. The specific radioactivity of bile cholesterol was less than that of plasma cholesterol at all time periods.The daily administration of epinephrine in oil over a period of four to seven weeks was accompanied by a more equal distribution of(14)C-cholesterol throughout the length of the aorta. An increase in the specific radioactivity of kidney cortex cholesterol, relative to that of plasma and kidney medullary cholesterol, also was observed in epinephrine-treated dogs.