Effects of starvation on liver microsomal P450 activity in juvenile Pleuronectes americanus.
Recent work has produced evidence to support the existence of a cytochrome P450 CYP2E1-like isoform in the marine fish, Pleuronectes americanus (winter flounder) (Wall K, Crivello JF. Toxicol Appl Pharmacol 1998;151:98-104). Starvation has been previously demonstrated to induce CYP2E1 activity (assayed as chlorzozazone-6-hydroxylase activity) in mammals and this study was undertaken to determine the effects of starvation on liver chlorzozaxone-6-hydroxylase and ethoxy-resorufin-O-deethylase activity (a CYP1A1 activity) in juvenile winter flounder liver microsomes. A 2-week starvation period resulted in a statistically significant increase in liver microsomal protein, and a decrease in liver lipid and liver glycogen. Ethoxy-resorufin-O-deethylase activity (pmol/min/mg microsomal protein) was reduced with starvation, chlorzoxazone 6-hydroxylase activity (pmol/min per mg microsomal protein) initially decreased but then increased over controls. When these activities were expressed per gm/liver (to account for the starvation-induced changes in liver microsomal protein), chlorzoxazone 6-hydroxylase activity doubled over control during starvation but ethoxy-resorufin-O-deethylase was not significantly changed. The effects of starvation on liver microsomal chlorzoxazone 6-hydroxylase and ethoxy-resorufin-O-deethylase activities are discussed in the context of the impact of physiological states on the ability of fish to detoxify marine xenobiotics.
Wall
K L
KL
Department of Physiology and Neurobiology, U-156, University of Connecticut, Storrs 06269-4156, USA.
Crivello
J
J
D000818:Animals; D001835:Body Weight / Q000502:physiology; D002753:Chlorzoxazone / Q000378:metabolism; D019363:Cytochrome P-450 CYP1A1 / Q000378:metabolism*; D019392:Cytochrome P-450 CYP2E1 / Q000378:metabolism*; D005432:Flounder / Q000378:metabolism*; D007202:Indicators and Reagents / Q000378:metabolism; D007527:Isoenzymes; D008099:Liver / Q000502:physiology; D008862:Microsomes, Liver / Q000201:enzymology*; D009929:Organ Size / Q000502:physiology; D013217:Starvation / Q000378:metabolism*
D007202:Indicators and Reagents; D007527:Isoenzymes; D019392:Cytochrome P-450 CYP2E1; D019363:Cytochrome P-450 CYP1A1; D002753:Chlorzoxazone