Zur enzymatischen Hydroxylierung von Cumarin, II. Die mikrosomalen Reaktionsprodukte bei verschiedenen Tierarten

Abstract

Coumarin-hydroxylating activity was investigaed in liver microsomes of slaughterhouse animals (beef, calf, sheep, pig), poultry (pheasant, chicken, pigeon), laboratory animals (rat, rabbit, hamster, guinea pig, mouse) and cold-blooded animals (eel, trout, frog). Lowest activity was found in cold-blooded animals; highest, in rodents. The most common reaction products were 3-, 7- and 8-hydroxycoumarin, o-hydroxy-phenyllactic acid and o-hydroxy-phenylacetic acid. 4-, 5- and 6-hydroxycoumarin were demonstrated in some systems. The composition of the products from the inorganic hydroxylation of coumarin showed no analogy to that from the microsomal hydroxylation. Rats of different strains formed negligible amounts of umbelliferone. The umbelliferone did not increase after induction with benzpyrene, phenobarbital and coumarin. In a quantitative comparison of umbelliferone formation among rodents, rabbits showed the highest hydroxylation activity. Lung, spleen, testis and kidney microsomes of some animals were also tried. Products from lung were qualitatively the same as from liver microsomes. If the NADPH-regenerating system was replaced by NADH in the enzyme incubation mixture, only quantitative differences were found in the reaction products.