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J Snegaroff

Publications and source records attributed to J Snegaroff.

4 recordsLinked to original sources
PubMed1989

Effects of the fungicide prochloraz on xenobiotic metabolism in rainbow trout: in vivo induction.

1. Rainbow trout were dosed with prochloraz by i.p. injection of sprayed food pellets. Cytochrome P-450, two P-450-dependent activities, and two conjugase activities were measured in vitro in microsomal or cytosolic fractions. 2. Prochloraz increased cytochrome P-450 in liver, intestine, and pyloric caeca: maximum response occurred at 30-100 mg/kg i.p. In cold conditions, this increase persisted for more than 8 days after injection. 3. Hepatic 7-ethoxycoumarin-O-dealkylase (ECOD) and 7-ethoxyresorufin-O-dealkylase (EROD) were inhibited by prochloraz except in one assay in warm water where they increased. In intestine and pyloric caeca, ECOD and EROD were not detected, even when cytochrome P-450 was increased. 4. UDP-glucuronosyltransferase (1-naphthol as substrate) was unchanged or inhibited after prochloraz dosing. 5. Glutathione-S-transferase (o-dinitrobenzene as substrate), was unchanged or inhibited by prochloraz. 6. The measured level of enzymic activities was the result of induction and inhibition by prochloraz residues. Variations in basal activities and perhaps in prochloraz interactions were due to temperature acclimatization.

Administration, Oral↗
PubMed1989

Effects of the fungicide prochloraz on xenobiotic metabolism in rainbow trout: inhibition in vitro and time course of induction in vivo.

1. Interactions between the fungicide prochloraz and the hepatic cytochrome P-450 of rainbow trout were studied by determination of enzymic activities in vitro using the microsomal fraction, and by kinetic studies. 2. Prochloraz inhibited 7-ethoxyresorufin-O-deethylase (EROD) in vitro. This inhibition was partially non-competitive: the enzyme-substrate-inhibitor (ESI) complex was catalytically active (68% of the activity of the enzyme-substrate complex). 3. Prochloraz in vitro inhibited aldrin epoxidase (AE) by a linear mixed-type mechanism. This inhibition might be high because of high affinity for prochloraz and lack of catalytic activity of the ESI complex. 4. Effects of prochloraz in vivo were studied as a function of time after intraperitoneal injection. Total cytochrome P-450 increased for more than 21 days. 5. EROD increased slightly at day 4 and then returned to control level. Kinetics showed an increase in apparent Km and Vmax. AE was strongly inhibited at day 4 (large increase in apparent Km) and then returned to control level in 21 days. 6. Spectral interactions with aniline showed strong inhibition and recovery to an activated level at day 21.

Animals↗
PubMed1985

UDP-glucuronosyltransferase: fluorometric determination and microcomputer method for bisubstrate kinetics analysis.

A method for analysing UDP-glucuronosyltransferase activity in rainbow trout hepatic microsomes is described, using 1-naphthol as a substrate and fluorometric determination of glucuronide. Kinetic constants are computed with a classical plot in a weighted regression. The computer uses the least-squares method for each value of a variable which is set and incremented. To get confidence intervals, the computer generates random values around experimental data (in a confidence interval they determine), and then computes again. With each simulation, a weighted regression with classical secondary plots gives simulated kinetic parameters. From each population of simulated values, an interval containing a given percentage of the population is determined.

Animals↗