Status of the toxicity reports of pesticides for their registration in Finland.

Recently, attention has centered on the validity of toxicity reports for the registration of pesticides. In Finland, a study was conducted to evaluate the validity of the toxicity reports of pesticides done in U. S.

Influence of environmental temperature on the induction of xenobiotic metabolism by beta-naphthoflavone in rainbow trout, Salmo gairdneri.

The response of hepatic microsomal cytochrome P-450 monooxygenase and UDPglucuronosyltransferase to a common inducer, beta-naphthoflavone, was investigated in rainbow trout acclimated to 5 or 17 degrees C. The hepatic microsomal 7-ethoxycoumarin-O-deethylase, 7-ethoxyresorufin-O-deethylase, and benzo[a]pyrene hydroxylase activities, measured at 5 or 17 degrees C, were induced at both acclimation temperatures. Maximum response of 7-ethoxyresorufin-O-deethylase and 7-ethoxycoumarin-O-deethylase activities to beta-naphthoflavone was obtained with doses of 5 mg/kg and above, both in warm- and cold-acclimated trout.

Xenobiotic biotransformation in the rainbow trout liver and kidney during starvation.

Microsomal cytochrome P-450-dependent activities in the kidney of fish starved for 6 weeks were significantly lower than in fed fish whereas these activities in the liver were only depressed after 12 weeks of starvation. Hepatic cytochrome P-450-dependent activities were depressed to varying extents after 12 weeks of starvation when different substrates were used. The content of hepatic cytochrome P-450 was not affected by starvation.

Catalytic and immunological comparison of coumarin 7-hydroxylation in different species.

Coumarin 7-hydroxylation activities were determined in the liver microsomes of eight different species: pig, mouse (three strains), rat, hamster, guinea-pig, rabbit, rainbow trout and crayfish. A high coumarin 7-hydroxylase activity was found in the microsomes of D2 mouse, rabbit, hamster and pig, an intermediate activity in case of B6 and AKR mice, rat and guinea-pig and a very low activity in rainbow trout and crayfish. In Ouchterlony immunodiffusion analysis our antibody against coumarin 7-hydroxylase specific cytochrome P-450 from D2 mice was able to form a weak precipitin line only with rat and hamster microsomes in addition to the three strains of mice (D2, B6, AKR) where the band was very sharp.