Modified Method Using a Somatostatin Analogue, Octreotide Acetate (Sandostatin^®) to Assess in Vivo Insulin Sensitivity

抄録

In order to evaluate the steady state plasma glucose (SSPG) method by using a new somatostatin derivative, octreotide acetate (Sandostatin^®) instead of somatostatin that we had used for the insulin sensitivity test, we examined whether octreotide was able to suppress C-peptide (CPR), glucagon (IRG), and GH to a similar degree to that achieved with somatostatin. A total of 52 studies were performed in 45 essential hypertensive subjects and 7 healthy subjects. Octreotide was given subcutaneously in a does of 50μg or 100μg 10min before the test (sc 50, sc 100 groups) or intravenously infused over 2h (10μg in bolus followed by a constant infusion, 50, 100, or 150μg/2h: iv 50, iv 100, iv 150 groups). In all of the groups the plasma immunoreactive insulin (IRI) concentration increased gradually after insulin injection and reached the steady state plasma insulin (SSPI) level between 40 and 60μU/ml at 60min through 120min. Plasma CPR at 120min was the most suppressed (by 67% of the basal level in iv 150 group during the study period), but on the other hand in both the sc 100 and iv 100 groups the plasma CPR concentration at 120min was suppressed by nearly 40%, but not significantly suppressed in either the sc 50 or the iv 50 group. Plasma IRG and GH were strongly suppressed after 60min in all the groups during the study period. Plasma glucose had increased significantly at 30min and reached the steady state at 90min through 120min in hypertensive and healthy subjects. The results indicated that the modified SSPG method with continuous intravenous infusion of Octreotide at 150μg/2h was adequate for the measurement of insulin sensitivity.