Response of Plasma Levels of Vitamin A to a Dose of Vitamin A as an Indicator of Hepatic Vitamin A Reserves in Rats

Abstract

Rats were fed diets deficient [-A] or sufficient [+A] (3 mg retinol equivalents/kg) in vitamin A, and without [-RA] or with [+RA] (12 mg/kg) retinoic acid supplemntation, for up to 33 days. Rats with plasma vitamin A levels ranging from 7 to 62 µg/dl were studied at intervals during progressive depletion of liver stores of vitamin A (expt. 2) and when liver stores were nearly exhausted (and low liver stores (<10 µg/g) of vitamin A, whereas an RDR of less than 40% was associated with plasma levels above 30 µg/dl and liver stores ranging from 3 to 100 µg/g.