Liver necrosis induced by thyroid hormone administration in rats fed ethanol

Recently it was observed that the hypothyroid state induced by propylthiouracil treatment reduced the elimination rate of ethanol. This was based on the fact that hypothyroid rats could only tolerate 10 g/kg/day of ethanol infusion over 24 It. Euthyroid rats tolerate 13 to 14 g/kg/day of ethanol infusion. In the present report it was postulated that thyroid supplements would increase the daily dose of ethanol that the treated rats could tolerate. Daily thyroid supplements, given intraperitoneally or orally, did. in fact, result in an increase in the elimination rate of ethanol. Death from ethanol overdose did not occur until the amount of ethanol given reached 16 to 19 g/kg/day. In addition, thyroxine supplements blunted or completely inhibited the urinary ethanol cycle. Submassive centrilobular liver necrosis was present in 9 of 10 rats given thyroid hormone and fed ethanol. Periportal duct metaplasia and fibrosis were also observed. Thus, thyroid supplements probably enhanced central hypoxia caused by ethanol to the point where ischemic necrosis developed. The latter healed by scar formation. Thyroid treatment completely prevented ethanol-induced steatohepatitis, indicating that the fatty change is responsive to the metabolic rate. (C) 2001 Academic press.