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)