The Effect of Intranasal Insulin on Hepatic and Intestinal Triglyceride-rich Lipoprotein Production

Inclusion Criteria: 1. Men and women, aged 18 to 60 years 2. Body mass index 20 to 40 kg/m2 3. Hemoglobin in the normal range. 4. Normal glucose tolerance in response to a 75g, 2-hr oral glucose tolerance test 5. Women of reproductive age should be on contraception (oral contraceptive pill or intra-uterine device/coil) for at least 2 months prior to and after the study. Exclusion Criteria: 1. Study participant with a history of hepatitis/hepatic disease that has been active within the previous two years. 2. Any current or previous history of biliary disease (including gall stones, biliary atresia and cholecystitis) or pancreatitis. 3. Any current or previous history of endocrine disease, dyslipidemia or malignancy 4. Any significant active (over the past 12 months) disease of the gastrointestinal, pulmonary, neurological, renal (creatinine \> 1.5 mg/dL) genitourinary, hematological systems, or has severe uncontrolled treated or untreated hyper/ hypotension (sitting diastolic pressure \> 100 or systolic \> 180 or systolic pressure \<100) or proliferative retinopathy 5. Use of immunosuppressive agents at any time during the study 6. Allergy to any study medication 7. Pregnancy or breastfeeding 8. Heavy smoker 9. Fasting blood glucose \> 6.0 mmol/l or known diabetes. 10. Any history of a myocardial infarction or clinically significant, active, cardiovascular history including a history of arrhythmia's or conduction delays on electrocardiogram, unstable angina, or decompensated heart failure. 11. Any nasal pathology. 12. Any laboratory values: aspartate aminotransferase \> 2x upper limit of normal ; alanine aminotransferase \> 2x upper limit of normal; thyroid-stimulating hormone \> 6 milliunit per litre