Abstract
The effects of tetracycline on the vitamin A contents of liver, small intestine and blood serum were studied in rats. By addition of 50 mg of tetracycline per kg of body weight to standard diet, vitamin A level of small intestine and blood serum was not significantly altered, but in the liver it was increased to one and a half times after four weeks feeding, and this was in a large part due to the ester form. The vitamin A contents of liver, small intestine and blood serum were determined in one, three, six and twenty four hours after an intravenous injection of vitamin A, 1 mg per kg of body weight, to the tetracycline administrated rats. The vitamin A level of small intestine indicated no significant variation. However, the vitamin A level of liver, reaching a maximum after three hours, rose more rapidly than that of the loading test group in normal rats. This result showed that vitamin A storage in liver was accelerated by tetracycline administration. The increase of vitamin A content in liver was probably due to the increased vitamin B_<12> by tetracycline administration, which made vitamin A conversion from carotene easier, thus resulting in added storage of vitamin A in liver.
