title: Increase in anti-carboxylesterase action of organophosphorothioates by nicotinamide adenine dinucleotide (NAD) in vitro.
abstract: 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.
mesh_terms: 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
chemical_list: D007306:Insecticides; D009946:Organothiophosphorus Compounds; D009243:NAD; D002268:Carboxypeptidases