[Effects of irradiation therapy and inhibiting drugs on the pituitary and its adenomas].

Radiation therapies of pituitary adenomas induce an increase in fibroses and nuclear pleomorphism. Most growth hormone (GH) secreting pituitary adenomas react to somatostatin analogues by a distinct decrease of GH secretion. In two thirds, levels of IGF-1 can be normalized. Some cases show a shrinkage of adenomas that correlates with fibrosis of the tumor. With these drugs, thyroid stimulating hormone secreting adenomas can also be treated. Prolactin secreting adenomas are mostly treated primarily with dopamine agonists. Up to 90% of cases show a strong decrease in hormone secretion and a distinct shrinkage of the adenomas based on strong decrease in adenoma cell volume. Long-term medication with high doses of glucocorticoids induces Crooke's cells in the anterior pituitary. These are suppressed ACTH cells and characterized by increased numbers of large lysosomes and dense bundles of cytofilaments.