EFFECT OF BENZYL ALCOHOL ON SUBCELLULAR LACTATE DEHYDROGENASE IN THE MALE RAT

Abstract

Benzyl alcohol (BA) can evoke cardiac toxicity on the premature newborn when given in conjunction with various injectable medications and/or I.V. flush solutions. Little is known on the underlying mechanism involved. This study evaluates the in vitro effect of BA on rat heart lactate dehydrogenase (LDH) isoenzymes in distinct subcellular fractions as a possible reflection of such toxicity. Both heart H and M subunits were measurable in the nuclear (NC), mitochondrial (MT) and cytoplasmic (CT) fractions of juvenile and adult rats. Presence of 90 mM BA exerted inhibitory action on MT LDH which was age-dependent, i.e., 67% and 59% inhibition of the H subunits occurred in the young and old rats, respectively. The MT M isoenzyme was not inhibited by 90 mMol BA in the young but a 29% inhibition occurred in the old animals. Changes determined in the H subunit of NC-LDH were less profound than those of the MT isoenzyme using the same concentration of BA. The latter concentration exerted only minimal action on the H subunit of the CT fraction of old but not of young rats. The results demonstrate BA toxicity on heart LDH in general and on its H subunit in particular. Also, a differential subcellular LDH sensitivity to BA toxicity was noted. The data suggest that BA adverse cardiac reaction may be associated with altered LDH activity.