GALLBLADDER EMPTYING AND CHOLECYSTOKININ AND PANCREATIC-POLYPEPTIDE RESPONSES TO A LIQUID MEAL IN PATIENTS WITH DIABETES-MELLITUS

To investigate gallbladder motility and its regulation in patients wit h diabetes mellitus (DM), we examined the gallbladder response to an i ntraduodenal test meal by measuring the temporal course of plasma chol ecystokinin (CCK) and pancreatic polypeptide (PP) levels. Eighteen pat ients with type 2 DM and 7 healthy subjects (controls) were enrolled. The gallbladder volume was calculated by the sum-of-cylinders method f rom ultrasonographic images, and plasma CCK and PP were measured by ra dioimmunoassays. No significant difference was found in either the gal lbladder response or in the CCK response between patients with DM. and controls. However, the fasting plasma PP level of patients with DM wa s more than tenfold higher than that of controls. The integrated PP re sponse (IPPR) of patients with DM to the test meal was 8.3-fold higher than that of controls. When patients with DM were grouped according t o whether they had been treated with insulin or not, the fasting plasm a PP of patients with DM without insulin treatment was significantly h igher than the level in those treated with insulin. These results sugg est that overproduction of PP-like immunoreactive substance(s) may occ ur in patients with DM, but the high plasma PP immunoreactivity does n ot appear to be related to the fasting gallbladder volume or to gallbl adder emptying and filling.