A Trial Evaluating the Effect of NN1250 at Steady State Conditions in Subjects With Type 1 Diabetes

Inclusion Criteria: * Type 1 diabetes mellitus (as diagnosed clinically) for at least 12 months * Current total daily insulin treatment lower than 1.2 (I)U/kg/day * Body mass index 18.0-28.0 kg/m\^2 Exclusion Criteria: * Subject who has donated any blood or plasma in the past month or more than 500 mL within 3 months prior to screening * Smoker (defined as a subject who is smoking more than 5 cigarettes or the equivalent per day) * Not able or willing to refrain from smoking and use of nicotine gum or transdermal nicotine patches during the inpatient period * Supine blood pressure at screening (after resting for 5 min) outside the range of 90-140 mmHg for systolic or 50-90 mmHg for diastolic