Eight out of 24 patients with GH- secreting adenomas (n = 8/24, 33.3%) had been treated with long-acting release octreotide for a mean period of 4.2 ± 1.1 months before operation; 4 out of 10 patients with ACTH-secreting adenomas (n = 4/10, 40%) had been treated with metyrapone for 4 ± 1.63 months before the surgery whilst all prolactinomas operated were resistant to cabergoline treatment prior to the surgery. This evidence concerns the gene POMC and adenoma.