Retinyl Ester (vitamin A Ester) and Carotenoid Composition in Human Liver

Surgical liver biopsy samples from seven diseased and five healthy human subjects, 3-33 years of age, were analyzed by reversed-phase high-pressure liquid chromatography for retinol (vitamin A alcohol), retinyl esters (vitamin A esters), and carotenoids. Total liver vitamin A values ranged from 7.8 to 2860 nmol/g liver (2.2 to 817 micrograms/g). As a percentage, liver retinol decreased with increasing liver reserves of vitamin A. Retinyl palmitate was the predominant vitamin A ester (57 to 83 mole%) in all samples, with retinyl stearate (5.5 to 11.4%), oleate (4.9 to 17.2%), and myristate plus palmitoleate (pair not resolved; 3.3 to 11.9%) next most common. Lesser amounts of retinyl linoleate, linolenate, and arachidonate were found. Normal livers had significant amounts of several carotenoids: lutein (0.2 to 16.2 nmol/g), lycopene (10.2 to 55.1 nmol/g), alpha-carotene (3.0 to 7.3 nmol/g), and beta carotene (5.8 to 25 nmol/g). Total carotenoid values ranged from 26.5 to 67 nmol/g in normal liver samples. There was no correlation between liver vitamin A and individual or total carotenoids in normal livers.