COLOCALIZATION OF GROWTH-HORMONE [GH] AND GLYCOPROTEIN SUBUNIT-ALPHA IN GH-PRODUCING PITUITARY-ADENOMAS IN ACROMEGALIC PATIENTS

Thirty-one consecutive cases of pituitary adenoma in acromegalic patients were studied by immunohistochemistry. All adenomas contained cells immunoreactive with the anti-a-subunit of gonadotropic hormones (alpha; 0.6-53 % of tumor cells) as well as with,anti-growth hormone (GH; 4-74% of tumor cells). In serial section study, most cells immunoreactive with anti-a were identical to cells immunoreactive with anti-GH. There was a positive correlation between the percentages of cells immunoreactive for alpha in GH cells [alpha(%)/GH(%)] and those for prolactin (PRL) in immunoreactive tumor cells {PRL(%)/[PRL(%)+GH(%)]} in mixed GH cell-PRL cell adenomas, suggesting that the alpha-subunit may play a role in emergence of PRL cells. reported [1, 5-7, 9-16]. Furthermore, Beck-Peccoz et al. [1] and Osamura et al. [14] reported that a-subunit and GH coexisted in the same tumoral cells of some GH-producing adenomas. We examined pituitary adenomas of 31 consecutive acromegalic patients by immunohistochemistry focused on alpha. All the tumors of acromegalic patients were demonstrated to express alpha.