ABSORPTION OF INSULIN IN THE PERITONEAL-CAVITY IN A DIABETIC ANIMAL-MODEL

This study was conducted to determine if different anatomical sites wi thin the peritoneal cavity have different capacities for portal insuli n absorption. Diabetic male Sprague-Dawley rats were studied. They wer e anesthetized and injected with streptozotocin. Blood glucose was mea sured before and after insulin (1 U/kg) was applied directly to the om entum, serosal surface of cecum, or parietal peritoneum or injected su bcutaneously. In a control group, blood glucose was measured at interv als without administering insulin. In addition, insulin labeled with r adioactive iodine (I-125) was applied to the same three locations in t he peritoneal cavity or injected intravenously. Animals were sacrifice d at 1, 5, 15, or 30 mins, and radioactivity was measured in excised l ivers and in blood samples. Blood glucose in the omental group respond ed to insulin with a greater hypoglycemic effect than in the peritonea l and control groups. The percentage of radioactivity recovered in liv er was significantly higher in the omental than in the serosal and per itoneal groups at 1 and 5 mins. The ratio of liver-to-blood radioactiv ity was also significantly higher in omental than in serosal and perit oneal groups and higher in the serosal than in the peritoneal group at 5 mins. The data suggest that, in this model, the omentum is a better site for insulin absorption than serosa or parietal peritoneum and th at significant portal venous absorption of insulin occurs.