EFFECTS OF A CHRONIC TREATMENT WITH OCTREOTIDE IN PATIENTS WITH FUNCTIONLESS PITUITARY-ADENOMAS

The effects of a chronic treatment with octreotide were evaluated in 1 9 patients affected with functionless pituitary adenomas. Octreotide c aused a significant decrease of GH and IGF-I levels in all the patient s and no significant change in thyroid, adrenal and gonadal function. In contrast, during the therapy, the glucose response to an oral gluco se tolerance test considerably increased and was delayed, while the in sulin response decreased and was delayed. Serum cr-subunit (alpha-SU) was above normal in 10 of 16 patients in which this evaluation was per formed: octreotide caused a significant decrease (p<0.01) of alpha-SU levels in 6 of these 10 patients. Octreotide did not induce any signif icant change in visual fields except in I patient, who had a great imp rovement of visual perimetry and a decrease of alpha-SU levels but unm odified CT scan features. In our series of patients, octreotide was in effective in reducing tumor mass. The efficacy of octreotide might rel y on the presence of somatostatin receptors on adenoma-cell membranes. Therefore patients with functionless adenomas to be treated with octr eotide might be identified with pituitary scintiscan using the recentl y available labeled In-111-octreotide.