The distribution of vitamin A in human liver

Abstract

The distribution of vitamin A in 15 human livers from autopsy specimens ranging in age from premature infants to 75 years was mapped. Regardless of the age or the amount of vitamin A present, the form of the distribution curve tended to be similar, with relative skewing toward the right (∼0.85) and an average CV of 63. Of 13 livers studied, the concentration of vitamin A in the right lobe was greater than that in the left in 10 cases, the differences being significant (P < 0.05) in seven of these cases. The caudal and central lobes tended to have somewhat lower concentrations of vitamin A than both right and left lobes. Among the 26 major lobes examined, no consistent pattern of vitamin A gradients was noted. In any given lobe, however, values of central, medial, and peripheral samples differed significantly in about half the cases, whereas concentrations in dorsal, internal, and ventral samples rarely showed a gradient. The distribution of vitamin A in the liver of other species analyzed—lamb, rat, and mouse—was characterized by a lower coefficient of variation (10 to 39) and showed either positive or negative skewness. These differences from the human may be either intrinsic or due to the relatively larger samples taken as well as to the high vitamin A concentrations present. Mean vitamin A values of samples taken from the midcentral portion of the right lobe generally agreed within 15% with the overall mean values. Thus with proper sampling technique, a single sample of liver may still serve as a useful indicator of the vitamin A status of an individual.