Ethanol and hypobarometric simulated high altitude: a gonadal-hepatic toxicity study in the male rat

Male rats were maintained on water or on 10% ethanol drinking fluid. They were pairfed for 30 d prior to exposure to simulated high altitude (approximately 6000 m) and for 78 d, during which they were exposed to simulated high altitude on alternate days. Corresponding controls were maintained at ambient pressure. The high-altitude animals showed loss in liver and epididymis weights compared to respective water controls as contrasted with increased spleen weight in ethanol-drinking rats exposed to high altitude. Hepatic mitochondrial aldehyde dehydrogenase (ALDH) was decreased, compared to controls, by hypobarometric pressure in water-drinking animals. Ethanol intake negated this effect. The kinetics of this inhibition show changes in Vmax without concomitant changes in the apparent Km. Hepatic alcohol dehydrogenase did not change by either treatment. Testicular and epididymal ALDH showed, statistically, no significant changes in specific activity as a function of exposure to high altitude. However, combined ethanol drinking and altitude exposure increased epididymal ALDH compared to water-drinking rats subjected to the same experimental conditions. The changes in liver and testicular weight and in the enzyme involved in the biotransformation of ethanol-derived acetaldehyde suggest the contribution of endocrinological and biochemical factors to hypoxia and to ethanol-evoked adverse responses studied.