Immunohistochemical colocalization of growth hormone (GH) and ? subunit in human GH secreting pituitary adenomas

Abstract

This immunohistochemical study disclosed that 9 of 15 GH secreting pituitary adenomas contained alpha subunit positive cells. These cases also contained PRL positive adenoma cells, but LH beta was negative. Of these 9 cases, 4 cases showed occasional FSH beta containing cells, 2 of these also contained a few TSH beta positive cells. By mirror section technique, variable numbers of adenoma cells were found to contain both GH and alpha subunit. Immunoelectron microscopically, both GH and alpha subunit were localized in secretory granules which suggested their co-release from the tumour cells. The presence of GH and alpha subunit in rough endoplasmic reticulum indicated their active production in the tumour. In the normal adult anterior pituitary gland, about 10% of GH cells contain FSH alpha, beta and LH beta subunits and had appearances suggesting the co-production of GH and FSH as well as LH. The colocalization of GH and FSH alpha is considered to be associated with the neoplastic transformation GH cells which possess the intrinsic potentiality of differentiation toward alpha subunit. However, the mechanism for the lack or deficiency of beta subunits in the neoplastic condition remains to be further investigated.

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

“…The immunohistochemistry and electron-microscopic features of human pituitary bihormonal adenomas producing PRL and GH have been described Halmi, 1982;Duello and Halmi, 1979;Ishikawa et al, 1983;Kovacs et al, 1984;Bassetti et al, 1986;Felix et al, 1986;Kovacs and Horvath, 1986a). Hormone colocalization in bihorm o d cells other than mammosomatotrophs was reported as well (Beck-Peccoz et al, 1986;Horvath and Kovacs, 1988;Osamura and Watanabe, 1987).…”

ACTH and α-Subunit are Co-expressed in Rare Human Pituitary Corticotroph Cell Adenomas Proposed to Originate from ACTH-Committed Early Pituitary Progenitor Cells

“…Primary antibodies used in this study were as follows: mouse anti-ACTH monoclonal antibody (at a dilution of 1:200, Dako, Carpinteria, CA), rabbit anti-α-subunit polyclonal antibody (at a dilution of 1:200, NIDDMK, NIH, Maryland), mouse anti-Pit-1 polyclonal antibody (at a dilution of 1:100, Santa Cruz, CA), rabbit anti-SF-1 polyclonal antibody (at a dilution of 1:100, Affinity BioReagents, CO), goat anti-T-pit polyclonal antibody (at a dilution of 1:50, Santa Cruz), goat anti-NeuroD1 polyclonal antibody (at a dilution of 1:100, Santa Cruz), rabbit anti-DAX-1 polyclonal antibody (at a dilution of 1:50, Santa Cruz), and goat anti-GATA-2 monoclonal antibody (at a dilution of 1:100, Santa Cruz). The specificity of anti-α-subunit antibody supplied by NIDDMK has been tested by immunohistochemical absorption test in an article by one of the authors (Osamura RY) [23]. We have been using the same lot of the rabbit anti-α-subunit antibody in our immunohistochemical staining.…”

Gene expression in pituitary adenomas: New insights

“…In a further tumour, the acidophil stem cell adenoma, GH is co-expressed with PRL although it is rarely secreted in excess . Growth hormone-secreting tumours are also associated with the expression of thyroidstimulating hormone (TSH) or the common ␣-subunit of the glycoprotein hormones (Furuhata et al, 1994;Kovacs et al, 1982;Osamura and Watanabe, 1987;White et al, 1986). These associations reflect the Pit-1 regulated cell lineage in the normal gland.…”