INFLUENCE OF SOMATOSTATIN TO BIOCHEMICAL PARAMETERS IN PATIENTS WITH PRIMARY HYPERPARATHYROIDISM

Somatostatin (SRIF) is effective in the nonoperative management of a v ariety endocrine tumors. A potential role of SRIF for treatment of pat ients with primary hyperparathyroidism (pHPT) has been suggested. In a controlled, prospective, triple-blinded, randomized clinical trial, t he somatostatin analogue octreotide (SMS 201-995, Sandostatin(R)) was evaluated in 40 patients with well documented pHPT. Amongst other bioc hemical parameters, serum calcium and -phospate and levels of parathyr oid hormone, calcitonin, and osteocalcin as well as octreotide were as sessed before and for 4 hours after a single iv. application of 200 mu g octreotide or placebo. SRIF-receptor autoradiography was performed in parathyroid tissue samples. Baseline values revealed a constellatio n of biochemical parameters typically found in pHPT. Following 200 mu g octreotide, no significant changes in any of the biochemical paramet ers investigated for were observed. Multivariate analysis was performe d to identify patient subpopulations in which any given combination of laboratory parameters changed in response to either drug or placebo. However, no 'responders' to octreotide were identified. 45% of patient s receiving octreotide, reported side effects. Parathyroid tissue samp les were negative for SRIF-receptor expression. It is concluded that a single dose iv. application of octreotide does not result in apprecia ble changes of biochemical parameters relevant in pHPT and carries a h igh rate of side effects. Furthermore, absence of SRIF-receptors in pa rathyroid tissue from patients with pHPT, together with lack of octreo tide effects, suggests that somatostatin-analogues may not be effectiv e in the non-operative therapy of pHPT.