Human Skeletal Muscle Lactate Dehydrogenase Activity in the Presence of Some Alcohol Dehydrogenase Inhibitors

Abstract

Methanol, ethylene glycol and other alcohol intoxications are complicated by severe acidosis which could be caused by formation of metabolic acids and additionally lactic acid production. An increasing nicotinamide adenine dinucleotide reduced/nicotinamide adenine dinucleotide oxidized (NADH/NAD) ratio during alcohol biotransformation is responsible for the induction of lactic acidosis. The main purpose of the present paper was to evaluate the effect of 4-methylpyrazole, cimetidine, ethylenediaminetetraacetic acid disodium salt, ethanol and methanol on lactate dehydrogenase (E.C. 1.1.1.27) activity and to discuss this issue. The activity of the enzyme was determined spectrophotometrically, in vitro using human enzyme skeletal muscle homogenates. 4-Methylpyrazole, cimetidine and ethylenediaminetetraacetic acid disodium salt at concentrations 0.01, 0.1, 1.0 mM and 12.5, 25.0, 50.0 mM of ethanol and methanol were studied. Our results showed that cimetidine increased lactate dehydrogenase activity as compared to the control at all tested concentrations. Such activity was noted for 4-methylpyrazole at 0.1 mM and higher concentration. By contrast, no significant effect on lactate dehydrogenase activity in the presence of ethylenediaminetetraacetic acid disodium salt, methanol and ethanol was observed.

In vivo 13C saturation transfer effect of the lactate dehydrogenase reaction

“…21 and references therein). After NMR parameters were adjusted, [2][3][4][5][6][7][8][9][10][11][12][13] C]glucose (20% wt/vol) was infused i.v. at 8 ml/hr over the first 5 min, followed by continuous infusion at a lower rate, which was adjusted over a small range to maintain plasma glucose concentration at hyperglycemic levels (23.3 Ϯ 2.6 mM).…”

“…The following imaging parameters were used: TR/TE ϭ 3050/30 ms, number of scans ϭ 2, number of slices ϭ 3, FOV ϭ 2.56 cm ϫ 2.56 cm, slice thickness ϭ 2 mm, and matrix size ϭ 128 ϫ 128. The in vivo spectroscopy parameters used to characterize the 13 C saturation transfer effect catalyzed by LDH in 9L and C6 glioma models were identical to those used for the [2][3][4][5][6][7][8][9][10][11][12][13] C]glucose and bicuculline infusion experiment described above.…”

“…After in vivo and postmortem MRS data acquisitions were performed in the bicuculline-treated rats infused with [2][3][4][5][6][7][8][9][10][11][12][13] C]glucose, the rat heads (N ϭ 4) were frozen in liquid nitrogen. The brain tissue was removed, weighed, and subsequently extracted using perchloric acid (12% perchloric acid solution, 3-4 mL/g of sample) as described previously (24).…”

“…Recently, it was shown that blocking LDH-A by RNA interference reduces the growth rate of cancer cells by approximately 100-fold (6). In vivo assessment of the LDH reaction may also be useful for studying other diseases with significantly elevated lactate concentration, such as panic disorder (7-9), metabolic acidosis (10), and Huntington's disease (11).…”

The Influence of Ethanol on Pyruvate Kinases Activity in Vivo, in Vitro, in Silico

“…That is why the decrease of NADH oxidation rates may be not just due to pyruvate kinase activity inhibition but due to lactate dehydrogenase activity inhibition too. According to the data from experimental studies lactate dehydrogenase activity is not affected by the 50 mM ethanol [4]. To approve these data and to test whether lactate dehydrogenase activity is inhibited by higher doses of ethanol we performed additional in vitro experiment.…”