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'-tetraethylthiuram disulfide, an inhibitor of aldehyde dehydrogenase) inhibited liver beta-alanine-oxoglutarate aminotransferase (beta-AlaAT I) activity yet activated tyrosine aminotransferase (TAT) in weanling rats in vivo. The effect on beta-AlaAT I was followed by the inhibitory expression of beta-AlaAT 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 (Kd) of 0.056 +/- 0.004 h-1. The synthesis of beta-AlaAT I in rat liver was estimated to be 1.56 x 10(-10) mol/g of wet tissue per hour at a steady state. A combination of ethanol and disulfiram also reduced beta-alanine-pyruvate aminotransferase (beta-AlaAT II) activity to 60% of the control after 24 h.