Pituitary adenomas: serum hormone levels and immunohistochemical staining for ACTH, GH and prolactin.

In 37 pituitary adenomas obtained by surgery the immunohistochemical staining for ACTH, GH and prolactin and the tumor size were related to the basal serum hormone levels. 5 adenomas were associated with Cushing syndrome, 9 with acromegaly, 17 with hyperprolactinemia and 6 were preoperatively diagnosed as inactive. A rather close correlation between immunoreactivity of tumor tissue and basal serum hormone levels was found for GH and prolactin whereas these two parameters were not significantly correlated in the corticotrophic adenomas examined. Furthermore there was no obvious correlation between serum hormone levels and tumor size. Several non immunoreactive adenomas showed slight hyperprolactinemia; all of them were macroadenomas with extended sellar lesions. This fact may be explained by disturbances in the hypothalamic-hypophyseal regulation of serum prolactin.