A NEW MODEL FOR PRODUCING VITAMIN-A-DEFICIENCY IN RATS

To produce a rapid depletion of vitamin A, an experimental approach ba sed on partial hepatectomy (60%) to remove stores and feeding a vitami n A deficient diet during recovery was tested in weanling and adult wi star rats. Plasma and liver vitamin A levels were determined at approp riate time points along with food intakes and body weights. Adult rats fed a deficient diet for a period of one month during regeneration, e xhibited significantly lower values (mean +/- SE) of liver vitamin A ( 176 +/- 19 mug/g) compared to controls (256 +/- 41 mug/g) receiving vi tamin A supplements. However, these levels are not in the deficient ra nge and the plasma vitamin A levels were not altered. Therefore, adult animals were not considered a suitable model for such experiments. In similar experiments with weanling rats, sham-operated controls kept o n a vitamin A-free diet showed a liver vitamin A concentration of 16 /- 1.2 mug/g after six weeks. Hepatectomized animals kept on a similar diet showed 5.2 +/- 1.1 mug/g liver in contrast to those fed on a vit amin A supplemented diet (328 +/- 27 mug/g). Also, the plasma vitamin A of hepatectomized animals on a vitamin A-deficient diet was very low (4.3 +/- 1/5 mug/dl) as compared to that in either supplemented or sh am-operated controls. Thus rapid deficiency of nutrients like vitamin A could be produced using a hepatectomy and regeneration model in wean ling rats, which otherwise may take much longer time.