THE EFFECTS OF TEMPERATURE ON THE UPTAKE AND METABOLISM OF BENZO[A]PYRENE IN ISOLATED GILL CELLS OF THE GULF TOADFISH, OPSANUS-BETA

The effects of acclimation temperature and acute temperature change on the uptake and metabolism of the procarcinogen benzo[a]pyrene (BaP) b y gill cells of the gulf toadfish, Opsanus beta, were examined. BaP wa s rapidly accumulated by isolated gill cells and uptake rates were dir ectly proportional to BaP concentration in the medium (1 to 100 mug/ml ). Uptake rates were higher in cells isolated from fish acclimated to 18-degrees-C when compared to cells from 28-degrees-C acclimated fish at all incubation temperatures. When cells were exposed to BaP at the respective acclimation temperatures of the fish, uptake rates were sim ilar (0.14 +/- 0.01 at 18-degrees-C and 0.12 +/- 0.01 gg BaP/s/10 mg c ells at 28-degrees-C). This finding is discussed in view of results wh ich showed a partial compensation of membrane fluidity in plasma membr anes isolated from fish from the two acclimation temperatures. At high er incubation temperatures, cells from fish acclimated to 18-degrees-C metabolized BaP at a greater rate than those at 28-degrees-C (49.6 +/ - 1.92 and 43.0 +/- 2.24 mug/g/8h, respectively, at 23-degrees-C). Low but detectable activities of common biotransformation enzymes (aryl h ydrocarbon hydroxylase, glutathione-S-transferase) and cytochrome P-45 0 content were found, however, no significant differences were evident between cells from fish acclimated to different temperatures.