Factors Affecting the Binding of Retinol to Serum and Its Components 1

Abstract

Summary

A Sephadex G-25, batchwise, semimicro, partitioning technique is presented for investigating the binding of retinol to serum components. Rat sera from normal, vitamin A-deficient, and vitamin A-supplemented animals exhibited differences in the binding of retinol. These differences were related to variations in the serum content of vitamin A and protein. The major protein fraction responsible for binding retinol was the α-globulin. Other fractions, namely γ-globulin and albumin, were also capable of binding retinol but to a lesser degree. Human and rat sera exhibited a larger amount of binding for ¹⁴C-retinol than for ³H-retinoic acid and ¹⁴C-β-carotene. Several unlabeled all-trans derivatives of vitamin A inhibited the binding of ¹⁴C-retinol.