Improved in vivo insulin effect during continuous subcutaneous insulin infusion in patients with IDDM

Abstract

It has recently been shown that conventionally treated IDDMs are insulin resistant. Using the insulin clamp technique, we studied the influence of metabolic status on the in vivo insulin effect in these patients. Eleven IDDMs, treated conventionally with diet and insulin for 10.7 +/- 5.6 yr, were studied before and after continuous subcutaneous insulin infusion (CSII) treatment (with a portable pump) for 6 mo. We found that conventionally treated diabetic subjects were extremely insulin resistant with regard to peripheral glucose uptake. Glucose uptake, at an insulin concentration of about 80 microU/ml, was 4.3 +/- 2.0 mg/kg X min before treatment compared with 11.5 +/- 4.0 mg/kg X min in normals (P less than 0.01). After pump treatment for 6 mo, metabolic control improved significantly (HbA1c decreased from 8.9 +/- 1.9% to 7.4 +/- 1.2%, P less than 0.01) and, parallel to that, glucose uptake increased about 80% to 7.5 +/- 3.5 mg/kg X min (P less than 0.01). The mean daily plasma FFA level decreased from 0.32 +/- 0.10 mmol/L to 0.21 +/- 0.07 mmol/L (P less than 0.01); this variable was negatively correlated to the glucose clearance rate (r = -0.62, P less than 0.01). There was no statistically significant change in mean daily plasma insulin and plasma growth hormone levels or in 24-h cortisol excretion in the urine (P greater than 0.1). The insulin binding capacity of serum IgG was also unchanged, and there was no significant relationship between this quantity and glucose clearance rates (r = 0.18, P greater than 0.1). We conclude that conventionally treated IDDMs are insulin resistant with regard to peripheral glucose uptake.(ABSTRACT TRUNCATED AT 250 WORDS)