RRC ID 2850
Author Kashiwada S, Goka K, Shiraishi H, Arizono K, Ozato K, Wakamatsu Y, Hinton DE.
Title Age-dependent in situ hepatic and gill CYP1A activity in the see-through medaka (Oryzias latipes).
Journal Comp. Biochem. Physiol. C Toxicol. Pharmacol.
Abstract We used a recently introduced strain of medaka, the see-through medaka, whose internal organs can be seen through the skin, to develop an in situ toxicity assay of ethoxyresorufin-O-deethylase (EROD) activity that detected fluorescence from resorufin, a metabolite of ethoxyresorufin and thus an indicator of CYP1A activity. EROD activity in the liver and gills of 2-week post-hatch see-through medaka exposed simultaneously to various concentrations of 3-methylcholanthrene and 200 microg/L ethoxyresorufin for 24 h was proportional to the 3-methylcholanthrene dose. Activities in the liver and gills peaked at 40 microg/L of 3-methylcholanthrene and then decreased at higher doses, possibly because of 3-methylcholanthrene toxicity. At 1-week post-hatch stage, however, constant high EROD activity was observed in controls and at all 3-methylcholanthrene doses. Four-week post-hatch see-through medaka exhibited less EROD activity than 2-week post-hatch see-through medaka, and activity in the liver peaked at 100 microg/L of 3-methylcholanthrene. Adult see-through medaka were not suitable for fluorescence detection owing to their thick skin, muscle and/or tissue. In tests of oxidative activity response to ethoxyresorufin, 1-day and 1-week post-hatch see-through medaka exhibited high intrinsic EROD activity in the liver, gills, and other organs in the absence of 3-methylcholanthrene. This intrinsic activity declined with growth and explained the high constant EROD activity at 1-week post-hatch stage.
Volume 145(1)
Pages 96-102
Published 2007-2
DOI 10.1016/j.cbpc.2006.07.005
PII S1532-0456(06)00164-5
PMID 16914386
MeSH Aging / physiology* Animals Cytochrome P-450 CYP1A1 / biosynthesis Cytochrome P-450 CYP1A1 / metabolism* Enzyme Induction Female Gills / enzymology* Gills / growth & development Larva / metabolism Liver / enzymology* Liver / growth & development Male Methylcholanthrene / toxicity Microscopy, Fluorescence Oryzias / metabolism* Oxazines / metabolism Oxazines / toxicity Oxidation-Reduction
IF 2.426
Times Cited 12
Medaka STII?