title: Formate excretion in urine of rats fed dimethylaminoazobenzene-rich diets: the possibility of formate formation from D-lactate.
abstract: This experiment was carried out to evaluate the possibility of degradation of d-lactate into formate and acetaldehyde. In order to induce hyperproduction of d-lactate in rats. Donryu male albino rats were fed diets containing 0.064% 3'-methyl-4-dimethylaminoazobenzene (3'-MDAB), 4'-methyl-4-dimethylaminoazobenzene (4'-MDAB) or 2-methyl-4-dimethylaminoazobenzene (2-MDAB) for 10 weeks. During the experiment, body mass, food and water intake and volume of urine were documented. Methylglyoxal, D-lactate and formate in the urine samples were determined. On the first day of the eleventh week, methylglyoxal, D-lactate, glutathione and enzymatic activities of demethylation and glyoxalase I and II in liver were measured. Methylglyoxal, D-lactate and clinical chemistry parameters of blood plasma were also measured. The levels of methylglyoxal and D-lactate in livers of rats fed 3'-MDAB were very high, while those of 2-MDAB fed-rats and the control group were the same. The fact that glyoxalase I activity and the level of glutathione, a cofactor of glyoxalase I, were high in the livers of the 3'-MDAB-fed rats can explain the elevated levels of methylglyoxal and D-lactate in the liver. The most striking results were the elevated formate levels in the urine of rats fed 3'- and 4'-MDAB in a precancerous state. The degradation of D-lactate, an end product of the methylglyoxal bypass, into acetaldehyde and formate was suggested as a possible way to explain the results.
authors.affiliation: Department of Physiological Chemistry, Faculty of Pharmaceutical Sciences, Okayama University, Okayama 700-8530, Japan.
authors.forename: Yuki
authors.initials: Y
authors.lastname: Kitamura
authors.forename: Michi
authors.initials: M
authors.lastname: Kawase
authors.forename: Shinji
authors.initials: S
authors.lastname: Ohmori
mesh_terms: D000079:Acetaldehyde / Q000378:metabolism; D000284:Administration, Oral; D000818:Animals; D015992:Body Mass Index; D003545:Cysteine / Q000378:metabolism; D004032:Diet; D004326:Drinking; D004435:Eating; D005561:Formates / Q000652:urine*; D005978:Glutathione / Q000378:metabolism; D019344:Lactic Acid / Q000378:metabolism*; D007791:Lactoylglutathione Lyase / Q000378:metabolism; D008099:Liver / Q000378:metabolism; D008297:Male; D011765:Pyruvaldehyde / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D013869:Thiolester Hydrolases / Q000378:metabolism; D004124:p-Dimethylaminoazobenzene / Q000008:administration & dosage / Q000378:metabolism*; D000099301:Hydroxyacylglutathione Hydrolase
chemical_list: D000079:Acetaldehyde; D003545:Cysteine; D005561:Formates; D005978:Glutathione; D019344:Lactic Acid; D007791:Lactoylglutathione Lyase; D011765:Pyruvaldehyde; D013869:Thiolester Hydrolases; D004124:p-Dimethylaminoazobenzene; D000099301:Hydroxyacylglutathione Hydrolase; C030544:formic acid