Changes of Growth Hormone-Containing Cells during Tumorigenesis and Subpassages of Estrogen-Induced Pituitary Tumors in Rats

Abstract

The changes of growth hormone-containing cells during the tumorigenesis and subpassages of the estrogen-induced pituitary tumors were studied with peroxidaselabeled antibody method.In a primary pituitary tumor induced with estrogen in a female W/Fu rat, growth hormone-containing cells were rather small and compressed away by the tumorous growths to localize mainly to the peripheral areas, corresponding with the unchanged acidophils in the routinely stained sections.The cells positively stained with the peroxidase-labeled antibody were scattered in a transplantable mammotropic pituitary tumor (MtT/F4). Since this tumor is well known to produce growth hormone in addition to prolactin and adrenocorticotropic hormone, a few non-functional growth hormone-containing cells which remained in the primary pituitary tumor were considered to have transformed to secrete growth hormone during the further subpassages.Further, the changes and variations of the hormonal activities of the estrogeninduced pituitary tumors were discussed from the view point of the different cellular populations.