[Erythrocyte insulin receptors in the ontogeny of chickens]

Specific binding of 125I-insulin by the erythrocytes was studied in the chick embryos, chicken and adult fowl. The binding was shown to decrease during ontogenesis. The maximal level of binding was observed in the chick embryos. Within a month after hatching, it decreased to the level of adult fowl due, mainly, to the decrease in the number of receptors per erythrocyte. This phenomenon can be accounted for both by the increase of insulin content in blood with age and the age changes of the population of erythrocytes. It is proved that during ontogenesis of the domestic fowl the decrease of a portion of immature erythrocytes in the peripheral blood with age accounts for the dynamics of binding observed. At the same time the affinity of hormone receptors increased but the influence of this factor on the binding pattern was not leading.