Investigating the effect of oxytocin on pancreatic endocrine functions by determining glucagon secretion during hypoglycemia in participants with type 1 diabetes.

Glucagonotropic effects of oxytocin will be examined in 16 participants with type 1 diabetes, during a hypoglycaemic clamp with concomitant intravenous infusion of synthetic oxytocin or placebo in a randomised, double-blinded design. This will determine the effect of oxytocin on the glucagon response to hypoglycemia. Additional changes in plasma/serum concentrations of insulin, C-peptide, glucose, glucose-dependent insulinotropic polypeptid (GIP) and glucagon-like peptide 1 (GLP-1) will be assessed.

Inclusion Criteria:

• Body mass index from 19 to 30 kg/m2
• T1D (diagnosed according to the criteria of the World Health Organization) with HbA1c <69 mmol/mol (<8.5%)
• T1D duration of 3-30 years
• C-peptide negative (stimulated C-peptide ≤ 100 pmol/l)
• Treatment with a stable basal-bolus or insulin pump regimen for ≥3 months

Exclusion Criteria:

• Anaemia (haemoglobin below normal range)
• Liver disease (alanine aminotransferase (ALT) and/or aspartate aminotransferase (AST) >2 times normal values) or present hepatobiliary and/or gastrointestinal disorder(s)
• Kidney disease (serum creatinine above normal range)
• Late microvascular complications except mild non-proliferative retinopathy
• Regular tobacco smoking or use of other nicotine-containing products
• Long QTc on electrocardiogram (ECG) at screening (≥0.45 seconds)
• Pituitary gland disease
• Treatment with any glucose-lowering drugs besides insulin
• Any ongoing medication or physical or psychological condition that the investigator feels would interfere with trial participation

The randomized order of infusions is blinded to both participant and investigator