Pineal Cell Proliferation in the Mouse.

Abstract

Summary In mice killed 2 days after birth, pineal parenchymal cells had a high proliferative rate as indicated by the large number of labeled nuclei. At 21 days, DNA synthesis occurred in less than 1% of the cells and by one month it had essentially ceased. The rate of DNA synthesis was lower in pineal parenchymal cells than in any other tissue of the adult mouse studied except for neurons of the central nervous system. No DNA synthesis was seen after injections of estrogen and progesterone in ovariectomized mice.