Effect of unbalanced diets on incorporation of delta-aminolevulinic acid into cytochrome P-450.
The in vivo syntheses of two liver microsomal cytochromes P-450 PB3a, P-450 UT50 [(1987) Eur. J. Biochem., submitted] (Mr 50,000, 52,000) have been estimated by measuring the specific activity 2 h after i.p. administration of delta-[3H]aminolevulinic acid to male Sprague Dawley rats. The animals were fed either a standard rat chow (5% lard, 22% casein) or unbalanced diets (high lipid, 30% lard or low protein, 6% casein) with or without 50 ppm Phenoclor DP6. The high-lipid diet supported a more rapid body weight gain but had little impact on cytochrome P-450 content, expressed either per whole liver or per mg microsomal protein, and on the incorporation of the precursor into cytochrome P-450. The latter was determined by measuring the radioactivity incorporated into the cytochrome P-450 fraction, partially purified by affinity chromatography, as well as into two cytochrome P-450 isozymes (Mr 50,000 or 52,000) purified by DEAE-52 cellulose ion-exchange chromatography. The low-protein diet, on the other hand, severely depressed body weight gain and cytochrome P-450 content as well as incorporation of radioactivity, the lower-Mr cytochrome (Mr 50,000) being particularly affected. However, when a potent inducer, Phenoclor DP6, was added to the low-protein diet, cytochrome synthesis was restored indicating that the effect was reversible.
D000622:Aminolevulinic Acid / Q000378:metabolism*; D000818:Animals; D003577:Cytochrome P-450 Enzyme System / Q000096:biosynthesis*; D004032:Diet; D007982:Levulinic Acids / Q000378:metabolism*; D008099:Liver / Q000378:metabolism; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains
D007982:Levulinic Acids; D000622:Aminolevulinic Acid; D003577:Cytochrome P-450 Enzyme System