Role of metabolic activation by cytochrome P450 in thioacetamide-induced suppression of antibody response in male BALB/c mice.
Effects of thioacetamide on antibody response to sheep red blood cells were investigated in male BALB/c mice. When mice were treated intraperitoneally with thioacetamide once, the antibody response was significantly suppressed at 200 mg/kg with hepatotoxicity. When mice were treated intraperitoneally with thioacetamide for 7 consecutive days, the antibody response was suppressed at 50 mg/kg without hepatotoxicity. To determine the possible role of metabolic activation by cytochrome P450 in thioacetamide-induced suppression of antibody response, mice were pretreated with phenobarbital intraperitoneally for 3 days, followed by intraperitoneal administration of 100 mg/kg of thioacetamide for 3 days. The elevated activities of serum aspartate aminotransferase and alanine aminotransferase by thioacetamide were potentiated by phenobarbital pretreatment. The suppression of antibody response by thioacetamide was potentiated by phenobarbital. In liver microsomes, the activities of P450 2B-specific enzymes were induced by phenobarbital. Our present results suggest that thioacetamide may require metabolic activation by P450 to its immunosuppressive form(s).
Kim
K H
KH
Toxicology Research Center, Korea Research Institute of Chemical Technology, P.O. Box 107, Yusung, Taejon, South Korea.
Bae
J H
JH
Cha
S W
SW
Han
S S
SS
Park
K H
KH
Jeong
T C
TC
D000410:Alanine Transaminase / Q000097:blood; D000818:Animals; D000917:Antibody Formation / Q000187:drug effects / Q000276:immunology*; D001219:Aspartate Aminotransferases / Q000097:blood; D001711:Biotransformation / Q000187:drug effects / Q000276:immunology*; D019362:Cytochrome P-450 CYP2B1 / Q000378:metabolism*; D004912:Erythrocytes / Q000276:immunology; D007165:Immunosuppression Therapy; D008099:Liver / Q000187:drug effects / Q000201:enzymology / Q000473:pathology; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008862:Microsomes, Liver / Q000187:drug effects / Q000201:enzymology; D009929:Organ Size / Q000187:drug effects; D010634:Phenobarbital / Q000494:pharmacology; D012756:Sheep; D013047:Specific Pathogen-Free Organisms; D013154:Spleen / Q000187:drug effects / Q000473:pathology; D013853:Thioacetamide / Q000633:toxicity; D013950:Thymus Gland / Q000187:drug effects / Q000473:pathology
D013853:Thioacetamide; D019362:Cytochrome P-450 CYP2B1; D001219:Aspartate Aminotransferases; D000410:Alanine Transaminase; D010634:Phenobarbital