Secretion of growth hormone (GH)-releasing hormone by GH-producing pituitary adenoma assessed by cell immunoblot analysis.

To detect growth hormone-releasing hormone (GHRH) secreted by monodispersed human GH-producing pituitary adenoma cells, the cell immunoblot assay was performed. GHRH-secreting cells were observed in 3 cases of GH-producing pituitary adenomas. The incidence of GHRH-secreting cells in the total cell populations was 0.24-3.42%. By contrast, no GHRH-secreting cells were observed in 2 cases of clinically nonfunctioning pituitary adenomas. The findings obtained by immunohistochemical studies for adenohypophysial hormones and for nuclear antigens of proliferative activity revealed that the incidence of GHRH-secreting cells is more related to the frequency of GH cells than to the proliferative activity in GH-producing pituitary adenomas.