Age-related changes in the numbers of mammotrophs, somatotrophs and mammosomatotrophs in the anterior pituitary gland of female rats: a flow cytometric study.

Abstract Age-related changes in the numbers of mammotrophs, somatotrophs, mammosomatotrophs, and the cells of other types in the anterior pituitary of female Wistar rat were measured by flow cytometry. The mammotrophs increased with age, and the somatotrophs decreased with senescence. The mammosomatotrophs increased remarkably in senescent rats, and these cells of the rats older than 21 months were about 10 times more than those of 3, and 12–13 months old rats. This result indicates that the stability of gene expression in cell differentiation is reduced in the aging process of the anterior pituitary.