Benzpyrene Hydroxylase Activity in the Gastrointestinal Tract1
نویسنده
چکیده
Quantitative and morphologic histochemical studies of the activity of the benz pyrene hydroxylase system in the gastrointestinal tract have been carried out. In nor mal rats activity is found only in the small intestine. In rats in which an increase in activity is induced by oral administration of 1,@-benzanthracene, activity is found throughout the entire gastrointestinal tract but varies in magnitude from one region to another. The effects of starvation and of a low-fat diet have been studied and were found to markedly lower the activity of the enzyme system. In addition to the rat, benzpyrene hydroxylase activity has been found to be present in the duodenum of mouse, guinea pig, rabbit, hamster, dog, monkey, baboon, and man. The possible role of this type of system as a protective mechanism against polycycic hydrocarbons which might reach the gastrointestinal tract is discussed.
منابع مشابه
Inhibition of induction of benzpyrene hydroxylase by nickel carbonyl.
Exposure of rats to nickel carbonyl by inhalation (0.2 mg Ni/liter of air/15 min) or intravenous injection (2 mg Ni/100 gm) was found to inhibit the induction of benzpyrene hydroxylase in lung and liver. Phenothiazine induction and fluorometric measurements of benzpyrene hydroxylase were performed by the methods of Wattenberg and co-workers (31, 32). Benzpyrene hydroxylase activities in lungs a...
متن کاملBenzpyrene hydroxylase activity and its induction by methylcholanthrene in Morris hepatomas, in host livers, in adult livers, and in rat liver during development.
There was no consistency of the induced levels among hepatoma lines, although all the rats were sacrificed exactly 6 hr after onset of feeding under controlled dietary regimens and 24 hr after a single intraperitoneal treatment with methylcholanthrene. Benzpyrene hydroxylase in fetal rat liver was very low in activity, and after birth a marked increase was observed. After administration of meth...
متن کاملInduction of increased benzpyrene hydroxylase activity by flavones and related compounds.
A study of relationships between the structure of flavones, flavanones, and chalcones and their capacity to induce increased 3,4-benzpyrene (BP) hydroxylase activity in the liver and lung of the rat has been carried out. Appropriate halogenation in creases inducing activity. In the compounds studied, hydroxylation reduces inducing capacity, but the corresponding methoxy compounds are active. Tw...
متن کاملOn the mechanism of inducing protection of the adrenal cortex against injury from 7,12-dimethylbenz(a)anthracene. I. Effects of inducers on benzpyrene hydroxylase activity.
Benzpyrene (BP) hydroxylase activity in the liver, small intestine, adrenal, and mammary gland of normal rats has been quantitatively assayed. There was only a very small amount of enzyme activity in the mammary gland. Administration of 3methylcholanthrene (3-MC) induced a marked increase in BP hydroxylase activity in the liver and intestine, but was without effect on the enzyme level in the ma...
متن کاملThe Stimulatory Effect of 3-methylcholanthrene on Benzpyrene Hydroxylase Activity in Several Rat Tissues: Inhibition by Actinomycin D and Puromycin.
The presence of benzpyrene hydroxylase activity in the small intestine, lung, and kidney of the normal rat has been shown by quantitative assay and compared with the level of activity in the liver. The intraperitoneal injection of methylcholanthrene in creased the level of activity found in each of the four tissues examined. The stimu lation by methylcholanthrene was inhibited by the simultaneo...
متن کامل