This project tend to investigate the affection of ketone bodies on brain metabolism. This will be done by measuring human cerebral uptake of energy substrates, together with functional parameters, using PET imaging and appropriate radiotracers under hyperketonemia in healthy subjects by ketone infusion.

Hypotheses

1. Increased levels of ketone bodies in healthy subjects leads to decreased glucose uptake by brain cells contributing to hyperglycaemia.
2. Increased levels of ketone bodies in healthy subjects leads to increased cerebral blood flow.
3. Altered oxygen consumption during hyperketonemia in healthy subjects.

Inclusion Criteria:

• Healthy
• BMI 20-30 kg/m2

Exclusion Criteria:

• smoking
• alcohol abuse
• severe comorbidity
• blood donation 6 month prior
• claustrophobia