Absorption of radiolabelled soluble insulin in type 1 (insulin-dependent) diabetes: influence of subcutaneous blood flow and anthropometry.

The rate of absorption of soluble insulin, and its relationships with subcutaneous blood flow (SCBF) and patients' anthropometry, were investigated in 12 male Type 1 (insulin-dependent) diabetic patients of less than 10 yr disease duration (age range: 23-29 yr; body mass index (BMI): 22.2-30.8 kg m-2). Simultaneous assessment of the absorption of 125I-labelled soluble insulin and SCBF (99mTechnetium clearance) were performed, on separate study days, for the anterior abdominal wall, anterior mid-thigh, and the upper arm injection sites. Absorption of 125I soluble insulin, including during the lag-phase, was determined by the two- and three-parameters biexponential models description of residual radioactivity levels at the injection site. Anthropometric measurements utilized were: BMJ, ultrasonic measurement of the subcutaneous adipose tissue layer, and caliper skinfold thickness at anterior abdominal wall, biceps, triceps, anterior mid-thigh and subscapular sites. Rate-constants for absorption of soluble insulin were positively correlated with SCBF (Spearman rank coefficient (rs) = 0.33-0.55; p < 0.01-0.001). An inverse relationship was observed between the duration of the lag-phase and SCBF (rs = -0.28 - -0.54; p < 0.05-0.001). Patients' degree of adiposity was inversely correlated with the rate of soluble insulin absorption (rs = -0.24 - -0.28; p < 0.05) and SCBF (rs = -0.28 - -0.43; p < 0.05-0.001). Consequently, faster absorption of soluble insulin, with shorter lag-phase duration, was noted for the abdominal and thigh sites for non-obese (BMI > 25 kg m-2) than obese patients (BMI < 27.5 kg m-2) (p < 0.05-0.01).(ABSTRACT TRUNCATED AT 250 WORDS)