Origin and fate of rat plasma cholesterol in vivo. Modelling of cholesterol movements between plasma and organs.
A cholesterol system model was developed in the rat following a single injection of red cells containing free (unesterified) [3H]cholesterol. The radioactivity of free and esterified cholesterol in the different parts of the system was measured during the 48 h following tracer introduction. The model consisted of seven compartments (red cell free cholesterol, plasma and liver free and esterified cholesterol, total cholesterol in the rapidly and slowly exchangeable carcass pools). The model was validated by the similarity between simulated and experimental values during the 48 h following tracer introduction. Both the fractional rate of cholesterol esterification in the plasma (0.44 h-1) and liver (0.01 h-1) and the fractional exchange rate of free cholesterol from the plasma towards the various organs (particularly 3 h-1 towards the liver for a total of 7 h-1) can be estimated with this model. The results show that cholesterol movements between the plasma and the different organs take place mainly through intense free cholesterol exchanges, resulting in a low net flux.
Magot
T
T
Laboratoire de Physiologie de la Nutrition (CNRS UA 646), Université Paris XI, France.
Frein
Y
Y
Champarnaud
G
G
Cheruy
A
A
Lutton
C
C
D000818:Animals; D002784:Cholesterol / Q000097:blood / Q000378:metabolism*; D002788:Cholesterol Esters / Q000097:blood / Q000378:metabolism; D004912:Erythrocytes / Q000378:metabolism; D007700:Kinetics; D008099:Liver / Q000378:metabolism; D008297:Male; D008433:Mathematics; D008954:Models, Biological; D051381:Rats; D011919:Rats, Inbred Strains; D014018:Tissue Distribution
D002788:Cholesterol Esters; D002784:Cholesterol