The purpose of this study is on one hand to verify the measurement conformity of the IRAP dosage and on the other hand to obtain normal values of the blood IRAP concentration on healthy volunteers.

This study consists of two visits, from two to five days apart.

The first visit :

• Healthy volunteers will be on an empty stomach.
• they will have a clinical examination, blood tests and blood samples will be taken to constitute a blood collection. the IRAP concentration will be measured with those samples.

The second visit : This visit will take place in an interval from 2 to 5 days after the first visit.

• Subjects will be on an empty stomach
• An oral glucose tolerance test (OGTT) of 3 hours will be performed. Blood samples will be taken three time 15 minutes apart at Baseline (before taking the glucose). And then after the glucose intake, blood sample will be taken every 15 minutes to measure insulinemia, blood glucose, and IRAP concentration.

Inclusion Criteria:

• Body mass index between 19 and 25 Kg/m²
• No intercurrent disease during the last week
• No chronic infectious disease
• No smoker, no alcoholic

Exclusion Criteria:

• history of : thyroid disease, liver or renal disease, endocrine and metabolic disease, cardiovascular disease, lung disease, gastroenterological disorders, psychiatric disease, Epilepsy
• Consumption of narcotic drug
• Blood donation dating less than 2 months
• Pregnancy or breast-feeding, or intent to become pregnant during the study period
• legal exclusion criteria

Healthy subjects distributed according to 3 age groups (40-49 years old , 50-59 years old, 60-70 years old). Every age bracket will be balanced in sex.