Endocrine Abstracts

Introduction: Impaired glucose tolerance and insulin resistance are frequently associated with acromegaly. The aim of this study was to assess the effect of octreotide-LAR treatment on glucose homeostasis in acromegalic patients.

Patients and methods: In this prospective study 16 naïve acromegalic patients were studied before and after 3-month therapy of octreotide-LAR (20 mg i.m. every 28 days). Diagnosis of active acromegaly was established on the basis of widely recognized criteria. In each patient glucose and insulin concentrations were assessed during the 75 g oral glucose tolerance test (OGTT) and HbA1c levels were measured. To estimate insulin sensitivity hyperinsulinemic euglycemic clamp method was used and homeostasis model assessment (HOMA-IR) and quantitative insulin sensitivity check index (QUICKI) were calculated.

Results: After 3 months of treatment no statistically significant change in plasma glucose levels both fasting and during OGTT (P>0.05) was found, but a significant reduction in HbA1c level (6.54±1.72% vs 6.02±0.78%) was noticed. A prominent reduction in insulin secretion was found after octreotide-LAR treatment compared to the moment of diagnosis (4.4±2.0 vs 12.1±9.6 mIU/ml, P<0.001). After treatment, there was a significant reduction in HOMA-IR (0.92 vs 2.27, P<0.05) and a significant increase in QUICKI (0.39 vs 0.34, P<0.05). In euglycemic clamp method a statistically significant increase in M value (4.52±2.34 vs 2.37±1.24 mg/kg per min) was noticed.

Conclusions: We concluded that in acromegalic patients octreotide-LAR therapy significantly improves glucose homeostasis by reducing insulin resistance.