Effects of Acute Ethanol Doses or Dietary Phenobarbitol with Carbon Tetrachloride Exposure on Vitamin A Status of Rats

Hepatotoxins such as ethanol and CCl₄ are known to adversely affect vitamin A metabolism, although the effects of acute exposure to these agents have received less evaluation. The purpose of this study was to determine the effects on vitamin A status after a series of acute ethanol doses or a series of CCl₄ inhalation challenges with concurrent phenobarbital exposure in the diet of rats. The depressed hepatic vitamin A seen after one ethanol dose was not sustained after repeated dosings. However, the significantly increased urine and liver radiolabeled vitamin A recovery after three acute ethanol exposure periods suggests adaptive physiologic and metabolic changes after the initial dose. The results of repeated CCl₄/Phenobarbital dosings on vitamin A status paralleled, for the most part, the ethanol results. Thus, the initial acute exposure of hepatotoxic agents causes metabolic changes that are not fully sustained as the animal adapts to these challenges.