Effect of aging on the storage and catabolism of vitamin A in mice.

In A/J mice, the mean total storage of vitamin A in the liver increased from birth to a maximum at 216 days, and then decreased at 644 days. The rate of deposition of intraperitoneally injected 11,12(3)H2-retinyl acetate in micellar form into stored retinyl ester in the liver was inversely related to the age of the mice, whereas rates of excretion of radioactive metabolites in the urine and feces were not systematically affected by age. The percent storage of a dose of radioactive vitamin A and the ratio of the amount stored to that excreted were higher in very young mice than in older mice. Vitamin A reserves in old mice (644 days), although lower than in adult mice (approximately 200 days), were still high and fully adequate to meet nutritional needs.