[Intestinal absorption of insulin with a new telemetric shuttle in dogs]

Telemetric shuttles for the in vivo investigation of the gastrointestinal tract have been available for sometime. We describe herein the use of a new shuttle model whose original features include: a) continuous, real time transmission of its location in the small bowel and accurate measurement of the gut length, b) controlled release of 1 ml of a given substance at any chosen site, allowing detailed investigation of intestinal absorption at different levels of the small bowel under physiological conditions. Small bowel length was measured in dogs using the shuttle and was later compared to the actual small gut length measured in the same animals at laparotomy. The telemetric measurements appeared to closely match the direct operative measurements. Insulin absorption from the canine small bowel was then investigated releasing different dosages of insulin together with the pancreatic enzyme inhibitors Soybean and Aprotinine and a surfactant (5-methoxysalicylate). By adjusting the dose of insulin released, the type of adjuvant substance delivered with it and the site of release in the small bowel, we have been able to precisely define the conditions of insulin absorption. Insulin as such is exclusively absorbed in the ileum when released in doses of 500 IU or higher and mixed with aprotinine. For absorption to take place the solution delivered by the shuttle needs to have the correct pH and natremic concentration.