Relationships among natriuresis, atrial natriuretic peptide and insulin in insulin-dependent diabetes

Abstract

Insulin-dependent diabetic patients have a large exchangeable body sodium pool, secondary to sodium retention. The pathogenesis of impaired natriuresis in insulin dependent diabetes remains to be elucidated. The present study examines the role of hyperinsulinemia, impaired atrial natriuretic release, and resistance to atrial natriuretic peptide action in determining sodium retention in normotensive and hypertensive insulin-dependent diabetic patients. Eight insulin-dependent diabetic patients had significantly higher daily sodium excretion rate (147 +/- 16 mmol/day; mean +/- SE) during conventional insulin treatment (daily plasma glucose: 11.6 +/- 1.2 mmol/liter; daily plasma insulin: 27 +/- 3 microU/ml) than during intensified insulin treatment (daily sodium excretion rate: 91 +/- 12, P less than 0.01; daily plasma glucose: 6.8 +/- 0.7, P less than 0.01; daily plasma insulin: 44 +/- 4, P less than 0.01). Daily sodium excretion rate was also significantly lower (107 +/- 13, P less than 0.01) in the same diabetic patients during intensified insulin treatment along with hyperglycemic clamp (daily plasma glucose: 12.8 +/- 0.3, NS; plasma insulin 48 +/- 4, P less than 0.01). Seven control subjects had lower extracellular liquid volume than eight insulin-dependent diabetic patients (11.0 +/- 0.8 l/1.73 m2 vs. 14.8 +/- 0.9, P less than 0.05) and also had baseline plasma atrial natriuretic peptide concentrations (18 +/- 5 pg/ml vs. 37 +/- 4, P less than 0.05). Atrial natriuretic peptide response to saline challenge was blunted in insulin-dependent diabetic patients when saline was administered on the basis of body surface area (90 mmol/1.73 m2.90 min) but not when administered on the basis of extracellular liquid volume (ECV) (8.2 mmol/liter ECV.90 min).(ABSTRACT TRUNCATED AT 250 WORDS)