Eligibility Criteria:
Inclusion Criteria:
* Healthy volunteers
* Aged between 35 et 60 years old
* Body mass index between 20 and 25
* Waist measurement \< 94 cm for men and \< 80 cm for women
* Normal basal glycemia, between 3,8 and 5,8 mmol/l
* Normal basal insulinemia, between 3 and 13 μUI/ml
* HbA1c \< 6%
* Total cholesterol \< 2 g/l
* LDL cholesterol \< 1,6 g/l
* HDL cholesterol 0,4 g/l for men and 0,5 g/l for women
* Triglyceride level \< 1,5 g/l
* For women not menopausal since at last one year or not surgically sterilised:
On-going contraception, physical or hormonal, excepted local methods (spermicidal, diaphragm, condom, cape)
* Type 2 diabetic patients
* Aged between 35 et 60 years old
* Stable type 2 diabetes mellitus: no ketoacidosis sign during last month
* HbA1c between 6 and 8% during the 3 months before study inclusion
* Monotherapy by metformin or diet only
* For women not menopausal since at last one year or not surgically sterilised:
* On-going contraception, physical or hormonal, excepted local methods (spermicidal, diaphragm, condom, cape)
Exclusion Criteria:
* Diabetes mellitus previously known
* Other on-going progressive illness
* Psychiatric illness, needing a chronic treatment
* Previous history of myocardial infarction, coronary artery disease, cardiac rhythm troubles, stroke, epilepsy, cranial trauma, pituitary surgery, disease likely to reduce the ability of absorption, diffusion or excretion of the radiotracer.
* Severe hypertension defined by par SAP \> 180 mmHg and/or DAP \> 110 mmHg
* Allergy to one of the components of the products used during the study
* Nuclear medicine examination during the 30 days prior to study inclusion
* Treatment likely to interfere with glucose metabolism
* Alcohol or drug intoxication
* Vegetarian or restrictive low-calory diet,
* Pregnant, parturient or breast-feeding women,
* Inappropriate way of life
* Type 2 diabetic patients.
* Previous history of myocardial infarction
* Severe hypertension defined by par SAP \> 180 mmHg and/or DAP \> 110 mmHg
* Previous history of coronary artery disease, cardiac rhythm troubles, stroke, epilepsy, cranial trauma, pituitary surgery, disease likely to reduce the ability of absorption, diffusion or excretion of the radiotracer.
* Psychiatric illness, needing a chronic treatment
* On-going insulin treatment
* On-going treatment other than metformin, likely to interfere with glucose metabolism
* Previous history of disease likely to reduce the ability of absorption, diffusion or excretion of the radiotracer
* Allergy to one of the components of the products used during the study
* Nuclear medicine examination during the 30 days prior to study inclusion
* Alcohol or drug intoxication
* Vegetarian or restrictive low-calory diet,
* Pregnant, parturient or breast-feeding women,
* Inappropriate way of life