B-8. Transsphenoidal Approach to the Pituitary Adenoma, with Special Reference to Postoperative Course of the Human Growth Hormone in Acromegaly

It has been known that eosinophilic granules of pituitary adenoma always associate with acromegaly, and further, the intensity of acromegaly depends on the amount of the these granules.However, we experienced a patient of pure eosinophilic pituitary adenoma (Bailey & Cushing, type 1.) without any sign of acromegaly.Because this case showed low concentration of immunoreactive human growth hormone (HGH), either the no-secretion of HGH or secretion of inactive HGH from eosinophilic granules was suspected.On the other hand, three patients of acromegaly showed high concentration of immunoreactive HGH (over 20-50 ng/ml) in plasma.After insulin-induced hypoglycemia and arginine infusion, plasma HGH rose to 80-120 ng/ml, while after the ingestion of 50 g glucose there was no change of plasma HGH.On histological examination these pituitary adenoma cells contained many eosinophilic granules.Electron-microscopic examination revealed many spherical secretory granules (200-400 mu), endoplasmic reticulums and mitochondria.Monolayer cultures of pituitary adenomas from these patients produced much HGH (1000 ng/day, 5 X 105) cells and continued to produce measurable concentration of HGH over the period of a month.On conclusion, eosinophilic granules are not simply responsible to acromegaly, but the amount of HGH released from eosinophilic granules of the pituitary adenoma is more importnat.