Increase in anti-carboxylesterase action of organophosphorothioates by nicotinamide adenine dinucleotide (NAD) in vitro.
The purpose of the present study was to investigate the relationship between chemical structure of organophosphorus insecticides and potentiation of anti-carboxylesterase (CEase) action of these insecticides by NAD in vitro (NAD-effect). Experiments using with three organophosphorothioates having ethoxy group except for diazinon exhibited greater NAD-effect than those having methoxy ones such as methylparathion and fenitrothion. In contrast, none of five organophosphates tested showed NAD-effect. And, 3-acetylpyridine adenine dinucleotide (Ac-py AD) among four derivertives of NAD was also found to have NAD-effect. These results suggested that P = S group in the molecule of organophosphorus insecticides was needed to occur NAD-effect. In addition, the extent of NAD-effect using acetylcholinesterase (AChE) was lesser than that of CEase, therefore, a higher susceptibility of liver microsomal CEase to organophosphorus insecticides may be explained, at least inpart, by NAD-effect.
D000818:Animals; D002268:Carboxypeptidases / Q000037:antagonists & inhibitors*; D004357:Drug Synergism; D066298:In Vitro Techniques; D007306:Insecticides / Q000633:toxicity*; D008297:Male; D008862:Microsomes, Liver / Q000201:enzymology; D009243:NAD / Q000494:pharmacology*; D009946:Organothiophosphorus Compounds; D051381:Rats; D011919:Rats, Inbred Strains; D013329:Structure-Activity Relationship
D007306:Insecticides; D009946:Organothiophosphorus Compounds; D009243:NAD; D002268:Carboxypeptidases