Immunoelectron microscopic evidence of mammosomatotrophs in human adult and fetal adenohypophyses, rat adenohypophyses and human and rat pituitary adenomas.

Immunoelectron microscopy, utilizing the double labelling immunogold technique, revealed the presence of mammosomatotrophs in human adult and fetal rat adult adenohypophyses as well as human and rat pituitary adenomas. These cells are characterized by the coexistence of GH and PRL not only in the same cells but also in the same secretory granules.

An immunocytochemical and ultrastructural study of adenohypophyses of mice transgenic for human growth hormone.

Adenohypophysial morphology in 12 mice transgenic for methallothionein-I-human (h) GH fusion gene was investigated by immunocytochemistry and electron microscopy. The sustained oversecretion of hGH stimulated body growth. The pituitary glands of 6-month-old transgenic mice were significantly decreased in weight and showed marked morphological changes in somatotrophs, lactotrophs, corticotrophs, and gonadotrophs.

Correlation study of serum prolactin levels, pituitary weights, number and ultrastructure of pituitary lactotrophs in female Long-Evans rats.

Twenty-five female, 23-month-old Long-Evans rats were sacrificed for investigation of correlations between serum prolactin levels, pituitary weights, numbers and ultrastructural features of pituitary lactotrophs. Serum prolactin levels measured by radioimmunoassay varied from 7.1 ng/ml to 1,534.

Adenohypophysial changes in mice transgenic for human growth hormone-releasing factor: a histological, immunocytochemical, and electron microscopic investigation.

The effect of protracted GH-releasing factor (GRF) stimulation on adenohypophysial morphology was investigated in six mice transgenic for human GRF (hGRF). All animals had significantly higher plasma levels of GH and GRF and greater body weights than controls. Eight-month-old mice were killed, and the markedly enlarged pituitaries were studied by histology, immunocytochemistry, electron microscopy, and immunogold method, using double labeling at ultrastructural level.

Double-labeling immunogold electron-microscopic study of hormonal colocalization in nontumorous and adenomatous rat pituitaries.

According to the one cell, one hormone theory, the pituitary gland is composed of 5 cell types which secrete 6 hormones. Recent investigations indicate that this theory must be modified, as there are some bihormonal cells containing 2 hormones, i.e.

Human fetal adenohypophysis. Electron microscopic and ultrastructural immunocytochemical analysis.

The pituitary glands were removed from 63 human fetuses from 5 weeks of gestation to term and studied by electron microscopy and ultrastructural immunocytochemistry to document the development of cell differentiation and hormone production in the adenohypophysis. At 5 weeks of gestation, Rathke's cleft was lined by columnar epithelium with abundant cytoplasmic glycogen and occasional secretory granules. By 6 weeks of gestation, cells resembling corticotrophs were identified; in 8-week-old fetuses, type I microfilaments were found in those cells.