Plasma somatostatin and plasma glucagon in long-term IDDM without residual B-cell function. No effect of different long-term metabolic control

Abstract

To further study the elevated plasma somatostatin (SRIF) and reduced plasma glucagon concentrations found in IDDM patients without residual B-cell function compared to normal controls, we investigated 39 such patients, randomly assigned to three different insulin treatment regimens; conventional therapy with two injections a day (CTh), insulin pump (CSII) and multiple injections (MI), for 1 year. They were given an arginine infusion (0.5 g/kg/20 min). The mean basal plasma SRIF values in the CTh, CSII and MI groups were 20.8±3.3, 18.6±1.8 and 20.6±2.8 pmol/1 and the mean basal plasma glucagon values were 30±5.7, 19±2.3 and 27±4.7 pmol/1, respectively. Both SRIF and glucagon increased in all groups in relation to arginine infusion. For both hormones, the mean values were highest in the CTh group, lowest in the CSII group, although the differences were not significant. The mean HbA_I values for the last 3 months within the test were 10.0±0.5, 8.8±0.3 and 9.1±0.5%, respectively, in the same order as above. The CTh group had significantly higher HbA_I values than the CSII group (p<0.02). We conclude that small differences in long-term blood glucose control are of inconsiderable importance for the islet hormonal response to arginine found in IDDM without B-cell function.

Key Words:

• arginine infusion
• C-peptide
• CSII
• growth hormone
• HbA_I
• multiple injections