In the gastro-intestinal tract, specialized cells secrete incretins after the ingestion of food. Two important incretins are GIP and GLP-1:
- GIP stands for glucose-dependent insulinotropic polypeptide
- GLP-1 stands for glucagon-like peptide-1.
These incretins are produced in the small intestine shortly after the intake of ethanol soluble carbohydrates (simple and double sugars), starch, proteins and fats. They cause the pancreas to secrete more insulin. This prevents blood glucose levels rising too much. Increased insulin levels are undesirable and harmful, especially for insulin resistant horses. They can cause laminitis or worsen the condition. This type of laminitis is called pasture-associated laminitis.
Why some horses are more prone to increased insulin levels than in others is not exactly known. The reason might be found in the genetic make-up of different animals.