INHIBITORY EFFECT OF ETHANOL ADMINISTRATION ON BETA-ALANINE-2-OXOGLUTARATE AMINOTRANSFERASE (GABA AMINOTRANSFERASE) IN DISULFIRAM-PRETREATED RATS

Ethanol in the presence of disulfiram (N,N,N',N'-tetra-ethylthiuram di sulfide, an inhibitor of aldehyde dehydrogenase) inhibited liver P-ala nine-oxoglutarate aminotransferase (beta-AlaAT I) activity yet activat ed tyrosine aminotransferase (TAT) in weanling rats in vivo. The effec t on beta-AlaAT I was followed by the inhibitory expression of beta-Al aAT I mRNA. The beta-AlaAT I activity was reduced with a pseudo-first- order profile with time, and the half-life was calculated to be 12.3 /- 0.83 h with the rate constant (K-d) of 0.056 +/- 0.004 h(-1). The s ynthesis of beta-AlaAT I in rat liver was estimated to be 1.56 x 10(-1 0) mol/g of wet tissue per hour at a steady state. A combination of et hanol and disulfiram also reduced beta-alanine-pyruvate aminotransfera se (beta-AlaAT II) activity to 60% of the control after 24 h.