Cholesterol turnover in plasma, aorta, muscles and erythrocytes in young and old rats.
Turnover of cholesterol was measured in 2 and 14 months old male rats (120 yound and 109 old) using a single intravenous injection of 3H-cholesterol and following the radioactivity of serum, aorta and muscle for 12 days. Blood cholesterol level is higher in the older animals. T 1/2 of the fast exchanging pool of cholesterol (compartment A) is 0.7 days in young rats and 0.9 days in the old rats )p is less than 0.025). T 1/2 of the slow exchanging pool of cholesterol (compartment B) in the young rats is 22 days and 32 days in the old rats (p is less than 0.025). Additional mathematical analysis showed that there is a decrease of the production of cholesterol and slower removal of cholesterol from both pools during aging. The effect of aging on cholesterol metabolism is exactly the opposite to the effect of cholestyramine as described in the literature. The speed of exchange of 3H-cholesterol between the plasma lipoproteins and erythrocytes is the same in the young and old rats both in vivo and in vitro measurements. Exchange of cholesterol between the blood and muscle or aorta is slower in older animals. Specific activity of the aorta in the old animals never reaches the specific activity of the blood. This shows that a part of the cholesterol pool in the aorta of old animals in metabolically very inert.
D000367:Age Factors; D000818:Animals; D001011:Aorta / Q000378:metabolism; D001158:Arteries / Q000378:metabolism*; D002784:Cholesterol / Q000097:blood / Q000378:metabolism*; D002792:Cholestyramine Resin / Q000494:pharmacology; D004912:Erythrocytes / Q000378:metabolism*; D008074:Lipoproteins / Q000097:blood; D008297:Male; D009132:Muscles / Q000378:metabolism*; D051381:Rats
D008074:Lipoproteins; D002792:Cholestyramine Resin; D002784:Cholesterol