Alimentary hyperglycemia in patients with subtotal gastrectomy is associated with decreased insulin secretion but not with insulin resistance.

BACKGROUND: It is not clear whether alimentary hyperglycemia in gastrectomized patients is related with glucose tolerance or not.
METHODS: Glucose tolerance, insulin secretion, and peripheral insulin sensitivity were evaluated in 36 patients who underwent subtotal gastrectomy for gastric cancer using the oral glucose tolerance test (OGTT), the intravenous glucose tolerance test (IVGTT) and the euglycemic hyperinsulinemic glucose clamp technique (Glucose clamp).
RESULTS: Patients were categorized into three groups by OGTT; 8 cases were in group I (normal), 19 cases in group II (alimentary hyperglycemia), and 9 cases in group III (glucose intolerance). Both glucose disappearance rate (K value expressed as, %/min) and insulinogenic index as determined by IVGTT were significantly lower in groups II (1.00 +/- 0.24, 0.21 +/- 0.18, respectively) and III (0.90 +/- 0.13, 0.11 +/- 0.14, respectively), compared with group I (1.58 +/- 0.71, 0.35 +/- 0.18, respectively). Peripheral insulin sensitivity as measured by glucose clamp was not decreased in groups II and III.
CONCLUSIONS: These results suggest that in patients with alimentary hyperglycemia, glucose tolerance was impaired due to a decreased pancreatic sensitivity to blood glucose and not due to insulin resistance.