Expression of glucocorticoid receptor in the brain of rats during postnatal ontogeny

Expression of glucocorticoid receptor protein in the hippocampus and frontal cortex of male and female rats during the 1st, 2nd, and 3rd weeks of life was studied by Western blot hybridization. In the frontal cortex, the concentration of receptor protein progressively increased from the 1st to the 3rd week of life; in females, expression of 94-kDa protein significantly surpassed that in males during the 1st week of life. In the hippocampus, expression of 94-kDa and 82-kDa proteins during the 1st week of life was higher in males. Moreover, expression of the major glucocorticoid receptor isoform (94 kDa) in this structure remained unchanged in all periods of the study in males, whereas in females it was low over the first 2 weeks of life and increased by the 3rd week. Variations in the expression of glucocorticoid receptors in the hippocampus of male and female rats coincide with changes in plasma corticosterone concentration during the early postnatal ontogeny.