Animal studies have shown that stimulation of the lingual lipid-receptor, CD 36, is accompanied by the rapid secretion of hormones in the digestive tract (incretines). We aim to determine in healthy humans whether the orosensory perception of fatty acids is followed by a modification in plasma levels of digestive tract hormones (cholecystokinin, GIP, GLP-1, secretin, pancreatic peptide, peptide YY, insulin) and metabolic markers from adipose tissue (leptin, ghrelin, adiponectin).

We also aim to determine whether the hormonal response induced by orosensory stimulation by lipids is modified:

• in patients with type 2 diabetes
• in obese non-diabetic patients We expect to show an increase in biological markers biological, and more particularly in certain digestive hormones such as Pancreatic polypeptide, GIP, GLP-1…after stimulation of the lingual lipid receptor, CD36. We will also determine whether or not this response is modified in patients with type 2 diabetes and in obese non-diabetic patients.

We also wish to measure the subjects' gustatory detection threshold for a fatty acid (linoleic acid), and to determine whether there is a relationship between the orosensory perception threshold for linoleic acid and the physiological status of the subjects. In order to achieve this, the thresholds for healthy subjects will be compared with thresholds for obese and diabetic subjects. Expected results: the threshold of detection for linoleic acid in healthy subjects will be lower than that in obese or diabetic patients.

Inclusion Criteria:

• persons who have provided written consent
• Healthy volunteers:
• Men > 18 years
• 19 <BMI < 25 kg.m-2
• Fasting triglyceridemia < 1.50 g/l
• Fasting glycemia < 1.10 g/l
• Without regular medical treatment
• Patients with type-2 diabetes:
• Men >18 years
• type 2 diabetes (fasting glycemia > 7 mmol/l at the diagnosis) treated with diet or diet + oral antidiabetics (metformin, and/or insulinsecretion agents [hypoglycemic sulphonamides, or glinides] and/or glitazones and/or acarbose)
• Stable oral antidiabetic treatment for 3 months
• Obese non-diabetic patients:
• Men > 18 years
• BMI 30 kg.m-2
• Fasting glycemia < 1.10 g/l
• HbA1c < 6.0%
• Absence of treatment with hypoglycemic agents (including benfluorex)
• Absence of medical treatment for obesity
• Absence of a history of surgery for obesity (band, by-pass) or gastric stimulator (type Tantalus)

Exclusion Criteria:

• Persons not covered by the national health insurance
• Smokers, or smoking cessation within the 3 months preceding inclusion
• Persons with eating disorders:
• Severe digestive disease (enteropathy with absorption disorders, inflammatory digestive disease)
• Pancreatic insufficiency
• History of pancreas surgery
• Type 1 diabetes
• Renal insufficiency
• Hepatic insufficiency
• Treatment with proton pump inhibitors, insulin, GLP-1 analogues, DPP-4 inhibitors