Plasma immunoreactive somatostatin response to arginine after glycemic control with continuous subcutaneous insulin infusion in type I diabetics.

The effects of 3 wk of near normoglycemia by continuous subcutaneous insulin infusion (CSII) on plasma immunoreactive somatostatin (IRS) responses to arginine (0.5 g X kg-1 X 30 min-1) in seven patients with insulin-dependent diabetes mellitus (IDDM) were compared with the same patients in poor glycemic control during conventional insulin therapy (CIT) and with seven normal controls. After 3 wk of CSII treatment, mean daily blood glucose and HbA1 decreased to mean (+/- SE) values of 129 +/- 6 mg/dl and 8.0 +/- 0.1%, respectively. Plasma free-insulin levels in IDDM patients 30 min before a meal during CSII were significantly higher than those during CIT or in normal controls. Fasting mean plasma IRS levels of the IDDM patients during CSII (7.3 +/- 1.4 pg/ml) were not different from those during CIT (8.4 +/- 1.3 pg/ml) and in normal controls (5.9 +/- 0.8 pg/ml). Arginine elicited a rise in plasma IRS during CIT in all seven IDDM patients during CIT and in the normal controls, with peak values of 18.2 +/- 4.1 and 12.5 +/- 1.8 pg/ml, respectively. However, no significant increase in plasma IRS was observed in all seven IDDM patients during CSII. The integrated values of plasma IRS during the arginine-infusion study of the IDDM patients treated with CIT were significantly higher than those of the normal controls. The increased integrated values of plasma immunoreactive glucagon response to arginine observed during CIT became normalized after CSII. These results suggest that glycemic control with CSII in IDDM patients suppresses the increased plasma IRS response to arginine that occurs during CIT.(ABSTRACT TRUNCATED AT 250 WORDS)