OBJECTIVE: To evaluate the short-term effects of Lanreotide Autogel on insulin sensitivity markers among acromegalic patients with pituitary tumors.
DESIGN: Prospective clinical trial with six months of follow-up.
SETTING: A tertiary endocrinology clinic.
MATERIALS AND METHODS: Naïve patients (patient No. 1 and patient No. 3) and patients who experienced prior somatostatin analogue treatment (patient No. 2, patient No. 4, and patient No. 5) were included. Before and after 6 months of Lanreotide Autogel therapy, insulin sensitivity in each subject was determined using homeostasis model assessment of insulin resistance and beta-cell function formula. Euglycemic hyperinsulinemic clamp test was also performed to evaluate whole insulin sensitivity and was indicated as an 'M' index.
RESULTS: All patients experienced reduction in their HOMA-beta. We noted major HOMA-beta decreases accompanied by pronounced increases in M indices for patients Nos. 1, 2 and 3 (1.03 vs. 8.22, 2.98 vs. 4.70, and 5.09 vs. 13.09, respectively). The increases in M indices of these patients were with marked decreases in GH levels (34.20 vs. 15.30 microg/l, 4.25 vs. 0.74 and 5.0 vs. 0.66 ng/mL, respectively). Minor decline in HOMA-beta and worsened M index and almost stable GH were observed in patients Nos. 4 and 5. Except for patient No. 3, all participants showed declining HOMA-IR.
CONCLUSIONS: Short-term Lanreotide Autogel treatment has been observed to improve M indices of acromegalic patients whose GH levels exhibited marked reduction. This amelioration seemed to be related to decreases in GH levels rather than to a direct drug effect.