Pituitary function was evaluated in eleven patients with large nonfunctioning pituitary adenomas before and 3 months after surgical adenomectomy. The longest anteroposterior dimension from the anterior wall to the dorsum of the sella on a lateral skull x‐ray ranged between 22 and 45 mm. All adenomas were confirmed histologically and had negative immunostaining for GH, PRL, ACTH and HCG. Based on the pre‐ and post‐operative pituitary function, the patients were divided into two groups. Group I included eight patients who had hypopituitarism pre‐operatively of whom five had partial recovery of pituitary function while three had persistent hypopituitarism. Group II included three patients who had normal pituitary function pre‐ and post‐operatively. Five patients of group I had high normal or slightly elevated serum PRL levels while one had a normal level and two patients had low levels pre‐operatively. TRH but not perphenazine resulted in a variable but definite rise in serum PRL preoperatively in patients with normal or elevated PRL level. In contrast, neither stimulus resulted in a rise in serum PRL in two patients with low basal levels. Serum PRL levels were normal in six patients and low in two others post‐operatively. Serum TSH levels were low in all eight patients with hypothyroidism. TRH resulted in a sustained release of TSH in three patients and was without effect in two patients pre‐operatively. Of eight patients with pre‐operative hypothyroidism, five recovered normal function and three remained hypothyroid. Of six patients with adrenal insufficiency pre‐operatively, two recovered normal pituitary—adrenal function while only two of eight patients recovered gonadal function post‐operatively. None of the eight patients recovered GH responsiveness to stimulation. All patients that recovered pituitary function had normal or slightly elevated serum PRL pre‐operatively. Our data indicate that recovery of pituitary function in patients with large pituitary adenomas and hypopituitarism may occur after surgical removal of the adenoma. One of the possible mechanisms of hypopituitarism in this setting would be interruption of the hypothalamic pituitary portal circulation by the large adenoma. An additional factor might be pressure necrosis and destruction of normal pituitary cells by the expanding adenoma. The extent of that might determine the degree of recovery of pituitary function.
|Original language||English (US)|
|Number of pages||10|
|State||Published - Jan 1 1982|
All Science Journal Classification (ASJC) codes
- Endocrinology, Diabetes and Metabolism