Changes in the Expression of Transcription Factor Oct4 during Postnatal Development of Adrenal Medulla

We analyzed the expression of the transcription factor Oct4 in the chromaffin cells during the postnatal development of the adrenal glands in rats. Single Oct4(+)-chromaffin cells with nuclear localization of the protein were found in the medulla, and their number increased in parallel with a decrease in the proliferative activity of cells. In postnatal development, 100% of chromaffin cells demonstrated high expression of tyrosine hydroxylase, which attested to their differentiation and functional activity. It was found that all Oct4(+) cells were differentiated chromaffin cells. An increase in the pool of Oct4-expressing cells after the completion of organ growth suggests the formation of a potential source for the physiological and reparative regeneration of the adrenal medulla.