Li J R, Kim D N
Steroids. 1979 Mar;33(3):317-26. doi: 10.1016/0039-128x(79)90008-4.
Optimal assay conditions for cholesterol 7 alpha-hydroxylase activity in swine liver microsomes were determined. The enzyme activity is induced three-fold by feeding cholestyramine to the swine. This suggests that cholesterol 7 alpha-hydroxylase is likely to be the rate-limiting enzyme for biosynthesis of bile acids in swine. The effects of various bile acids on cholesterol 7 alpha-hydroxylase in swine microsome and "solubilized" cholesterol 7 alpha-hydroxylase activity have been studied. There is no significant reduction of native microsomal enzyme activity. However, except for chenodeoxycholic acid, most of the bile acids tested exerted significant inhibition on "solubilized" cholesterol 7 alpha-hydroxylase. This finding suggests that bile acids could interact with and regulate the rate-limiting enzyme for bile acid formation in swine.
确定了猪肝微粒体中胆固醇7α-羟化酶活性的最佳测定条件。给猪喂食消胆胺可使该酶活性提高三倍。这表明胆固醇7α-羟化酶可能是猪胆汁酸生物合成的限速酶。研究了各种胆汁酸对猪微粒体中胆固醇7α-羟化酶和“溶解的”胆固醇7α-羟化酶活性的影响。天然微粒体酶活性没有显著降低。然而，除鹅去氧胆酸外，大多数测试的胆汁酸对“溶解的”胆固醇7α-羟化酶有显著抑制作用。这一发现表明胆汁酸可能与猪胆汁酸形成的限速酶相互作用并对其进行调节。
