Effect of hydrazine upon vitamin B12-dependent methionine synthase activity and the sulphur amino acid pathway in isolated rat hepatocytes

Kenyon, Susan H. and Waterfield, Catherine J. and Asker, Daniel S. and Kudo, Mariko and Moss, David W. and Bates, Timothy E. and Nicolaou, Anna and Gibbons, William A. and Timbrell, John A. (1999) Effect of hydrazine upon vitamin B12-dependent methionine synthase activity and the sulphur amino acid pathway in isolated rat hepatocytes. Biochemical Pharmacology, 57 (11). pp. 1311-1319. ISSN 0006-2952

Full content URL: http://dx.doi.org/10.1016/S0006-2952(99)00032-5

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Item Type:Article
Item Status:Live Archive

Abstract

The effect of the industrial chemical, hydrazine (4-12 mM), on methionine synthase (EC 2.1.1.13) activity and levels of the sulphur amino acids homocysteine, cysteine, and taurine as well as GSH were investigated in vitro in isolated rat hepatocyte suspensions and monolayers in order to explain some of the adverse in vivo effects of hydrazine. None of the concentrations of hydrazine were overtly cytotoxic in hepatocyte suspensions (measured as lactate dehydrogenase [LDH] leakage) after 3 hr. However, after 24 hr in culture cells treated with 12 mM, hydrazine showed a significant increase in LDH leakage. Methionine synthase activity was reduced by hydrazine (8 and 12 mM) in suspensions (by 45 and 55%, after 3 hr) and monolayers (12 mM; 65-80% after 24 hr). This was not due to nitric oxide production and the inhibitor of nitric oxide synthase, Nomega-nitro-L-arginine, failed to protect against the hydrazine-induced loss of ATP and GSH and the reduction in urea synthesis at 24 hr. Homocysteine export was increased by 6 mM hydrazine, and total taurine content of treated cells was increased by 12 mM hydrazine. Thus, hydrazine was found to have several important and possibly deleterious effects on some parts of the sulphur amino acid pathway.

Keywords:Hepatocytes, hydrazine, GSH, methionine synthase
Subjects:A Medicine and Dentistry > A100 Pre-clinical Medicine
B Subjects allied to Medicine > B220 Toxicology
Divisions:College of Science > School of Life Sciences
ID Code:5296
Deposited On:09 Jun 2013 09:23

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