Dietary amino acids and hepatic microsomal drug metabolism in Syrian hamsters

The source and level of amino acids fed to Syrian hamsters modified hepatic microsomal drug metabolism in this species, and the effects differed between the two sexes. Drug-metabolism systems of the liver were evaluated in Syrian golden hamsters fed three sources of amino acids, casein (C), lactalbumin (L) and supplemented casein (SC), each at four levels (4, 10, 20, and 40 gm/100 gm of diet). A protein-free (PF) diet was fed to an additional hamster group. Hepatic microsomal protein content, cytochrome P450 content, and aryl hydrocarbon hydroxylase (AHH) and aniline hydroxylase (ANH) activities were measured after three weeks of feeding the diets. Microsomal protein content generally rose with increasing protein levels in the diets from 0 to 20 gm/100 gm diet, except for C-fed females, in which values did not differ from those fed PF diet. Supplemented casein supported no increased levels of microsomal protein when fed from 4-40 gm/100 gm diet; however microsomal protein rose from increased dietary C and L up to 20 gm/100 gm diet in males and from increased L up to 20 mg/100 gm diet in females. Cytochrome P450 content was influenced in animals fed C and L by amino acid level in a manner similar to observed effects on microsomal protein. However, consumption of 10 gm SC/100 gm diet by males resulted in the highest cytochrome levels. AHH activity rose with increased dietary amino acids for both male and female hamsters; and maximal activities occurred in hamsters fed the 20 or 40 gm protein/100 gm diet levels. ANH activity was influenced both by amino acid source and level with both sexes; the feeding of C resulted in a higher activity of this enzyme than that of SC. ANH activity was highest in hamsters fed the 20 and 40 gm amino acid/100 gm diet levels.