Octreotide is an 8-chain amino acid analog of somatostatin. Somatostatin and its receptors occur naturally in multiple sites within the body and serve a suppressive role in endocrine hormone release. When octreotide, which has a considerably longer half-life than somatostatin, is combined with a radioactive isotope, receptor-based imaging can be performed to visualize tumors with high concentrations of somatostatin receptors. Tumors of neural crest origin — Pituitary adenomas, islet cell tumors, medullary thyroid carcinomas, pheochromocytomas, carcinoids, and paragangliomas — all express high levels of somatostatin receptors. We present the first reported positive octreotide scan of a Hürthle cell carcinoma of the thyroid and, more important, discuss the role of octreotide scanning in otolaryngology, which has not yet been reviewed by our literature.

AbstractSomatostatin receptors expressed on tumor cells form the rationale for somatostatin analog treatment of patients with somatostatin receptor-positive neuroendocrine tumors. Nevertheless, although somatostatin analogs effectively control hormonal hypersecretion by GH-secreting pituitary adenomas, islet cell tumors, and carcinoid tumors, significant differences are observed among patients with respect to the efficacy of treatment. This may be related to a differential expression of somatostatin receptor subtypes among tumors. In addition, the property of somatostatin receptor subtypes to undergo agonist-induced internalization has important consequences for visualizing, as well as for therapy, of receptor-postive tumors using radioisotope- or chemotherapeutic-compound-coupled somatostatin analogs. This review covers the pathophysiological role of somatostatin receptor subtypes in determining the efficacy of treatment of patients with somatostatin receptor-positive tumors using somatostatin analogs, as well as the preclinical and clinical consequences of agonist-induced receptor internalization for somatostatin receptor-targeted radio- and chemotherapy. Herein, the development and potential role of novel somatostatin analogs is discussed.

ABSTRACTProlonged administration of norethynodrel with mestranol had a pronounced and selective influence on hormonal target tissues in middleaged male hamsters. Results were compatible with work in other species, which shows the primary site of action to be the pituitary-gonad axis. Markedly reduced gonadotrophin and androgen levels were indicated by atrophy of testes and accessory reproductive glands. The high dosage used also resulted in significant renal hypertrophy, but structural integrity was not conspicuously different from that of controls.The test agents had no influence on the incidence or metastatic propensity of a wide variety of spontaneous tumours, including adenomatous polyps and adenocarcinoma of the intestine, adrenal cortical nodular hyperplasia or adenoma, islet cell adenoma, melanoma, or adenocareinoma of Cowper's gland. This result is in accord with our previous observations that spontaneous tumorigenesis in the hamster is largely independent of hormonal physiology but is influenced by hormones to the extent that tumorigenesis may require some degree of normal tissue or cell integrity.