Аннотация:Hormone-binding and some other physicochemical properties of an estrogen-binding protein (EBP) from the female and male rat pancreas in partially purified specimens were studied. Kinetic parameters of the hormone-protein interaction were found to be the same for males and females. However the concentration of binding sites for estradiol in females was higher than that in males. The female and male EBP exhibited nearly the same specificity for hormonal compounds except for some estrogens and androgens, whose competitive efficiency was higher in males. These sex differences were found not to be ascribed to diverse intensity of hormonal metabolism during incubation with male and female EBP specimens. The data obtained are suggestive of sex differentiation in the quantity and/or quality of low molecular "accessory" factor modifying EBP hormone-binding properties.