[Mammotropic and somatotropic pituitary cells in spontaneous mammary tumor bearing C3H female mice. A quantitative electron microscope study].

Pituitaries of mammary tumor-bearing mice (C3H) were examined by quantitative electron microscopy. The results indicate that considerable modifications occur in mammotropic and somatotropic cells. Both types show an increase of the surface of the endoplasmic reticulum and a decrease of the volume of secretory granules (in percent of cytoplasmic volume), suggesting a heightened secretory activity of these cells during mammary carcinogenesis.