Endocrine Abstracts

Lanreotide has long been used in the therapy of GH secreting pituitary adenomas and other somatostatin receptor positive neuroendocrine tumors.

Aims: To determine the impact on glucose metabolism of the 6 months of lanreotide therapy, beside of the antisecretory and antiproliferative effects.

Patients and methods: Seven patients with active acromegaly treated with lanreotide, admitted in the Department of Neuroendocrinology, Institute of Endocrinology, Bucharest. They were evaluated by oral glucose tolerance test (OGTT) with serum glucose, GH (IRMA-sensitivity 0.02 ng/ml) and insulin (RIA-sensitivity 1 mU/ml), serum IGF1/upper limit for age and sex ratio, HOMA-IS and insulin sensitivity index during OGTT (ISI _OGTT) were calculated for insulin sensitivity measuring and computed tomography.

Results: Seven patients (3 males), aged 44+19 years were treated with lanreotide for 6+3 months after unsuccessful surgery and radiotherapy. Basal GH decreased to normal values (<2.5 ng/ml) in 5/7 patients, most being after minimum 6 months after radiotherapy. In 3/7 patients, nadir of GH during OGTT decreased to <1 ng/ml and IGF1/ upper limit for age and sex ratio became <1. Tumor diameters did not change with >25% in neither of patients. Before lanreotide treatment, 1 patient had secondary diabetes mellitus and 1 had impaired glucose tolerance. During chemotherapy, basal glycemia insignificantly decreased from 115.8+49.3 to 103.5+39.9 mg/dl and 120 min glycemia after glucose upload from 138.2+90.7 to 111.1+83.9 mg/dl. Indexes of insulin sensitivity increased statistically insignificant, but the patient with impaired glucose tolerance showed normal glucose tolerance after 6 months of lanreotide therapy. HOMA IS was 0.19+0.05 vs 0.47+0.031 mmol/l*mU/ml and ISI_OGTT was 2.2+0.7 vs 5.3+0.3 during treatment.

Conclusion: Six months of lanreotide, a long acting somatostatin analogs therapy showed antisecretory effect in 5/7 acromegalic patients, without altering glucose metabolism.