Vitamin A metabolism under nutritional stress
Rao, M.S.; Thyagarajan, K.; Kishore, G.S.; Cama, H.R.
International Journal for Vitamin and Nutrition Research. Internationale Zeitschrift für Vitamin- und Ernahrungsforschung. Journal International de Vitaminologie et de Nutrition 44(2): 151-158
1974
ISSN/ISBN: 0300-9831 PMID: 4855398 Document Number: 80368
Sixty-six weanling female albino rats were on stock diet until weight was 120 to 125 g, when 1 group of 6 rats was killed. The remaining rats were divided into 5 groups of 6 fed on 0.5% casein diets and 6 control rats on 18% casein diet. All received vitamin A according to bodyweight. Two groups were killed after 25 and 50 days and 3 continued on the same diet for about 75 days, when typical signs of deficiency were evident in the rats deprived of protein. At that stage another group was killed. The 2 remaining groups were transferred to the 18% casein diet and the vitamin A supply was discontinued; one group was killed 15 days and the other 30 days later. Rats deprived of protein stored more vitamin A/g tissue in liver and kidney than control rats, but plasma contained less vitamin A. During repletion vitamin A in all 3 tissues became comparable with that in normal controls. The activities of the enzymes of vitamin A metabolism, retinaldehyde oxidase, retinaldehyde reductase and retinyl palmitate hydrolase, were low compared with controls, but they returned to normal when rats were given the high-protein diet.