The effect of vitamin B12 on tetracycline-induced fatty liver.

The effect of vitamin B12 on the metabolic alterations due to tetracycline toxicity was studied experimentally on laboratory animals. Treatment of Sprague-Dawley rats with 120 or 250 mg tetracycline (i.p.) per kg per day for two or three days caused an accumulation of lipids, mainly triglycerides in the liver of 75% of animals studied, while phospholipid level tend to decrease. These doses are approximately twice and four times the recommended maximum dose for man. In the present work no direct relationship was observed between dose of tetracycline and hepatic accumulation of triglyceride, although livers of rats treated with 250 mg tetracycline/kg appeared uniformly pale yellow. Elevated serum triglyceride was found predominantly in rats treated with 120 mg/kg, while there was no obvious difference between serum triglyceride of rats treated with 250 mg tetracycline and control rats, indicating a block in the release of hepatic triglycerides. Where protection by vitamin B12 was studied, the vitamin was given i.m. (50 microgram/animal) 3 hours before the injection of 120 mg tetracycline per kg. There was a good evidence that lipid abnormalities caused by tetracycline improved by vitamin B12. Thus both hepatic and serum total lipid and triglycerides were significantly lower than those of rats treated with tetracycline, although hepatic total cholesterol was significantly increased as in case of tetracycline only.