Open AccessInfluence of Bile Acids on the Activity of Rat Liver 3‐Hydroxy‐3‐methylglutaryl Coenzyme A Reductase
Author(s) -
Hamprecht Bernd,
Nüssler Christa,
Waltinger Gudrun,
Lynen Feodor
Publication year - 1971
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1971.tb01207.x
Subject(s) - cholic acid , taurine , reductase , coenzyme a , enzyme , cyp8b1 , biochemistry , in vivo , in vitro , microsome , cholesterol , chemistry , enzyme assay , bile acid , hydroxymethylglutaryl coa reductase , 7 dehydrocholesterol reductase , biology , hmg coa reductase , amino acid , microbiology and biotechnology
1 The rate limiting enzyme of cholesterol biosynthesis, 3‐hydroxy‐3‐methylglutaryl coenzyme A reductase, is found in the microsomal fraction of a liver homogenate. It is markedly inhibited in vitro by the cholesterol metabolites cholate, deoxycholate, chenodeoxycholate and their taurine conjugates only at unphysiologically high concentrations. 2 The inhibition by taurochenodoxycholate is non‐competitive and only partially reversible. Therefore, the effect of bile salts in vitro is interpreted as a non‐specific detergent effect. 3 Feeding of cholic acid in the diet prevents the diurnal rhythm of the activity of 3‐hydroxy‐3‐methylglutaryl coenzyme A reductase. The activity decreases with increasing time of feeding of cholic acid. 4 The specific activity of the enzyme decreases with increasing age of the animal. 5 It is concluded that the effect of bile salts in vitro on this enzyme cannot account for their effect in vivo . Rather, it is suggested that in vivo bile salts interfere with the de novo ‐synthesis and/or the degradation of the enzyme.