Age Changes in the Fine Structure of Anterior Pituitary of the Mouse.

Electron micrographs of the ananterior pituitary gland of the Swiss albino mouse reveal that the cytoplasm of chromophobes, acidophiles and basophiles contain granules, a double-membraned system and mitochondria in varying amounts. The nuclear membrane appears to be double. With aging the nuclear membrane becomes irregular in outline, the nuclear cortex becomes dense, the mitochondria become enlarged and vacuolated, and the double-membraned system fragments. The implications of these observations are discussed.