Gastrin and growth of the alimentary tract in the streptozotocin-diabetic rat.

Mucosal growth in small intestine of the streptozotocin-diabetic rat is increased; insulin treatment decreases growth toward normal. Gastrin is trophic to the alimentary tract. Therefore, we measured gastrin and growth of the alimentary tract in controls, diabetics, and insulin-treated diabetics. Mucosal growth of the small intestine increased at 10 days of diabetes and increased further by 20 days. Serum and antral gastrin did not respond to diabetes at 10 days. At 20 days, mean antral gastrin was increased in all diabetic groups, but the increase was significant only for a hyperphagic ad libitum-fed diabetic group, which also showed increased serum gastrin. Insulin treatment decreased serum gastrin but only partly reversed the increased mucosal growth in diabetics. We conclude that 1) gastrin is not the primary cause for increased small intestinal mucosal growth in diabetes, inasmuch as gastrin did not respond to diabetes at 10 days when mucosal growth was increased, and decreased serum gastrin in insulin-treated groups was associated with increased mucosal growth; and 2) diabetes appears to increase gastrin.