Introduction: Insulin resistance due to chronic growth hormone (GH) excess in acromegaly and inhibition of insulin and glucagon secretion by long-acting somatostatin analogues (SSA) used in the treatment are the main reasons of the impaired glucose tolerance in acromegalic patients.
Objective: We aimed to determine the effect of long-acting SSA, Octreotide-LAR and Lanreotide-Autogel treatment on glucose homeostasis regarding the insulin resistance and pancreatic ß-cell function.
Method:Totally 30 patients (17 male, 13 female; mean age: 44,63±11,85 years) were enrolled in this cross sectional study. Serum IGF-1 concentrations and glucose, insulin, GH levels at 0., 30., 60. and 120. minutes during 75 gr oral glucose tolerance test (OGTT) were measured. Patients were categorized into 3 groups according to their disease activity. Patients cured after operation, patients with active disease after operation but in remission after SSA therapy and patients with active disease after operation and SSA therapy were defined as cure, remission and active group, respectively For the interpretation of glucose homeostasis, formulas for insulin resistance (HOMA-IR, QUICKI) and ß-cell function (HOMA-ß, Insulinogenic index) were used.
Results:There was no statistically significant difference between groups for HOMA-IR and OUICKI (p=0,78; p=0,781) and also between disease activity and insulin resistance. For the insulinogenic index, which is the marker of early phase of insulin secretion, there was a borderline difference in significance between groups (Insulinogenic index; cure group: 0,97; remission group: 0,52; active group: 0,33; p=0,076). Although no statistically significant difference between groups, HOMA-ß of cure group was higher than the other two groups independent of disease activity (HOMA-ß: cure group %104; active group %72; remission group %59; p=0,384). In the cure group, the insulin levels during OGTT, the peak insulin secretion during OGTT were higher and the time to reach the peak level was lower than the other groups but not significantly (p=0,420; p=0,176). When parameters determining the glucose homeostasis and disease activity were examined, only statistically significant negative correlation between insulinogenic index and nadir GH was found (r=0,367; p
Key words: Acromegaly, insulin resistance, HOMA-IR, HOMA-ß, QUICKI, insulinogenic index, somatostatin analogues
|
