Effects of in vivo benzo(a)pyrene treatment on liver microsomal mixed-function oxidase activities of gilthead seabream (Sparus aurata).
Benzo(a)pyrene [B(a)P] treatment of gilthead seabream, 25 mg/kg, i.p. for 5 consecutive days, did not cause any significant changes in ethylmorphine N-demethylase and aniline 4-hydroxylase activities of liver microsomes. The same treatment did not alter the liver microsomal cytochrome b5 content, NADH-cytochrome b5 reductase and NADPH-cytochrome P450 reductase activities. However, benzo(a)pyrene treatment caused a 2-3-fold increase in 7-ethoxyresorufin O-deethylase (7-EROD) activity of gilthead seabream liver microsomes. Although, upon treatment, total cytochrome P450 content of liver microsomes increased about 1.7-fold in 1990 fall, no such increase was observed in spring 1991. However, a new cytochrome P450 with an apparent M(r) of 58,000 was observed on SDS-PAGE of liver microsomes obtained from benzo(a)pyrene treated gilthead seabream. Besides, in vitro addition of 0.2 x 10(-6) M benzo(a)pyrene to the incubation mixture inhibited 7-ethoxyresorufin O-deethylase activity by 93%. Gilthead seabream liver microsomal 4-ethoxyresorufin O-deethylase activity was characterized with respect to substrate concentration, amount of enzyme, type of buffer used, incubation period and temperature.
Arinç
E
E
Department of Biology, Middle East Technical University, Ankara, Turkey.
Sen
A
A
D000818:Animals; D001564:Benzo(a)pyrene / Q000633:toxicity*; D002021:Buffers; D019363:Cytochrome P-450 CYP1A1; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism; D008862:Microsomes, Liver / Q000201:enzymology*; D006899:Mixed Function Oxygenases / Q000187:drug effects*; D010088:Oxidoreductases / Q000378:metabolism; D010473:Perciformes; D012710:Serum Albumin, Bovine; D013379:Substrate Specificity; D013696:Temperature
D002021:Buffers; D012710:Serum Albumin, Bovine; D001564:Benzo(a)pyrene; D003577:Cytochrome P-450 Enzyme System; D006899:Mixed Function Oxygenases; D010088:Oxidoreductases; D019363:Cytochrome P-450 CYP1A1