Acute hyperglycaemia causes elevation in plasma atrial natriuretic peptide concentrations in Type 1 diabetes mellitus K. McKenna, D. Smith, W. Tormey and C. J. Thompson Abstract Aims To examine the effect of acute hyperglycaemia on atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) concentrations in Type 1 diabetes. Methods The study was two limb, randomized, and single-blind. Eight Type 1 diabetes subjects were clamped at euglycaemia by intravenous infusion of insulin. When euglycaemia was established, the insulin infusion rate was left unaltered for the remainder of the protocol, and an intravenous infusion of either 500 ml 0.9% saline or 500 ml 10% dextrose was administered over 1 h. Blood was collected for estimation of plasma glucose, ANP and BNP concentrations at 30 min intervals for 2 h from the start of the infusion period. One week later, each subject received the alternate infusion. Results are expressed as mean 6 standard deviation, and were analysed by ANOVA. Results Baseline plasma glucose (P = 0.8), ANP (P = 0.8) and BNP (P = 0.8) concentrations were similar on the study days. Plasma glucose rose with dextrose (6.1 + 0.5±15.1 + 2.8 mmol/l, P = 0.9). Plasma ANP concentrations were unaltered by saline infusion (76.5 6 14.7±77.7 6 15.2 pg/ml, P = 0.9), but increased with dextrose infusion (79 6 14±134 6 17.1 pg/ml, P < 0.0001), and were higher with dextrose than saline infusion (P < 0.0001). Plasma concentrations of BNP were not signi®cantly altered by infusion of either dextrose (5.1 6 3.9±9.3 6 5.4 pg/ml, P = 0.63) or saline (4.3 6 3.5± 6 6 5.2 pg/ml, P = 0.84). Conclusions Plasma concentrations of ANP, but not BNP, rise in response to acute hyperglycaemia in Type 1 diabetes. Diabet. Med. 17, 512±517 (2000) Keywords atrial natriuretic peptide, brain natriuretic peptide, diabetes mellitus. Abbreviations ANP, atrial natriuretic peptide; BNP, brain natriuretic peptide; UAER, urine albumin excretion rate Introduction It has been suggested that atrial natriuretic peptide (ANP) may contribute to the development of microalbuminuria in diabetes mellitus [1]. Plasma ANP concentrations have Dept of Diabetes, Beaumont Hospital, Dublin 9, Ireland These data were presented at the 1999 American Diabetes Association Annual Meeting in San Diego Received 4 November 1999; revised 6 March 2000; accepted 12 May 2000 Correspondence to: Dr C. Thompson, Diabetes Centre, Beaumont Hospital, Dublin 9, Ireland. E-mail: chris.thompson@beaumont.ie 512 ã 2000 Diabetes UK. Diabetic Medicine, 17, 512±517