US EPA

1480078 

Technical Report 

Hepatic microsomal mixed-function oxidase in the frog, Xenopus laevis 

Doherty, MJ; Khan, MAQ 

1981 

Yes 

Comparative Biochemistry and Physiology - Part C: Comparative Pharmacology
ISSN: 0306-4492 

PESTAB/81/1368 

Biochem 

2 

221-228 

English 

6112107 

10.1016/0306-4492(81)90019-8 

https://www.scopus.com/inward/record.uri?eid=2-s2.0-0019448518&doi=10.1016%2f0306-4492%2881%2990019-8&partnerID=40&md5=78ff246b9bad358971f29edbda528896
Exit
 

PESTAB. Hepatic microsomal mixed-function oxidase (MFO) of the frog, Xenopus laevis, appears to be similar to that of fish and mammals. However, the levels of protein in liver microsomes, and specific contents and activity of cytochrome P450, cytochrome c reductase, aldrin and chlordane epoxidase, and naphthalene and chlordene hydroxylase of frog liver are about 30-40% of these of male rats or mice and about 65% of that of the adult bluegill. The levels are extremely low in frog larvae but keep increasing after metamorphosis, reaching the adult levels between 9 and 12 wk after tail absorption. The levels of enzyme activity (measured with naphthalene, aldrin, dieldrin, and chlordene) correspond to the P450 concentration and not the level of cytochrome c reductase activity. In adult frogs the enzyme activity can be affected only slightly by diets. Inducers of P450 (hexobarbital) and P448 (beta-naphthoflavone) cause about 50% increase in cytochrome P450 concentration but did not increase P450 catalyzed reactions. (Author abstract by permission)