title: Factors determining to biotransformation of cholesterol to bile acids in the rat: development of a new model.
abstract: This paper proposes a model for cholesterol metabolism in the rat based on extensive data obtained on rats in isotopic equilibrium with radioactive cholesterol. These data reveal that the rate of bile acid synthesis is closely related to cholesterol input. Hence the transformation of cholesterol into bile acids is conceived as a determinative process for the dynamics of the cholesterol system in the rat. This process is not per se regulated if the definition of regulation is as follows: to maintain constant a variable. In fact, the control of the transformation is dependent on the particulate transport of the plasma lipoproteins into the liver. In other words, from a physiological point of view, the process governing the net removal of cholesterol from the plasma into the liver is the limiting step for the cholesterol transformation into bile acids. Temporary losses or gains of cholesterol by the system modify the flow of the cholesterol transformation into bile acids during a transitory period. The effect of the exogenous taurocholate is so interpreted. Because this bile acid seems to act initially on the capacity of the liver to esterify free cholesterol, there results a loss of cholesterol which cannot be transformed into bile acids.
mesh_terms: D000818:Animals; D001647:Bile Acids and Salts / Q000096:biosynthesis*; D001711:Biotransformation; D002784:Cholesterol / Q000378:metabolism*; D007700:Kinetics; D008099:Liver / Q000378:metabolism*; D008954:Models, Biological; D051381:Rats
chemical_list: D001647:Bile Acids and Salts; D002784:Cholesterol