@entity35 small intestine possesses @entity1447 mixed function oxidase activity and is thus potentially capable of activating procarcinogens during absorption. The low spontaneous @entity5 incidence at this site may be due partially to the detoxification activity of the intestinal mucosa. To study the contribution of the intestine to the metabolism of foreign chemicals, microsomes have been obtained from @entity35 small intestine by a procedure facilitating recovery of preparations with consistently high enzyme activities and abilities to activate some selected promutagens in the Salmonella mutagenicity assay. Intestinal microsomes from animals with and without pretreatment with inducers have been used for investigations of biochemical properties and ability to activate several mutagens in the Salmonella plate incorporation assay. The effects of microsomal protein concentration and inhibitors were also studied. The results are compared with data obtained using liver microsomes from the same animals. Despite the induction of lower numbers of revertants, intestinal microsomes were at least as efficient as liver preparations for the activation of all the promutagens used when the data were corrected for @entity1447 contents. Differences in dose-response curves for certain mutagens using liver and intestinal microsomes are discussed in relation to variation in metabolism of promutagens. Activation was linearly dependent on microsomal protein concentration, for both liver and small intestinal microsomes. The intestine was generally less susceptible to the effects of @entity1447 and P-448 inducers, although sensitivity to orally administered @entity109 was increased by extending treatment times. SKF525A and @entity11423 inhibited microsomes from both sources, equal inhibition being observed for each type following incorporation of the inhibitor, although they differed in their ability to activate @entity5997 in the presence of the deacylase inhibitor, @entity7034 . The data are discussed in relation to the possible role of the small intestine in metabolic activation in vivo and the utility of microsomes therefrom for the in vitro detection of putative dietary carcinogens.

Characterization of a microsomal fraction from XXXX small intestine for metabolic activation of some promutagens.

@entity1447 :: ('25251(Tax:10116)', 'Gene') :: ['cytochrome P-450'] @entity11423 :: ('MESH:D019324', 'Chemical') :: ['beta-naphthoflavone'] @entity5 :: ('MESH:D009369', 'Disease') :: ['tumour'] @entity109 :: ('MESH:D010634', 'Chemical') :: ['phenobarbitone'] @entity35 :: ('10116', 'Species') :: ['rat', 'Rat'] @entity5997 :: ('MESH:D015073', 'Chemical') :: ['2-acetylaminofluorene'] @entity7034 :: ('CHEBI:28741', 'Chemical') :: ['NaF']
@entity35 :: (10116,Species) :: ['rat']
