THE ROLE OF DIETARY ZINC IN MODIFYING THE ONSET AND SEVERITY OF SPONTANEOUS DIABETES IN THE BB WISTAR RAT

The goal of this study was to determine whether zinc supplementation i n the diet of diabetes-prone BE Wistar rats will delay or prevent the onset of overt diabetes. Male Wistar BE rats were fed diets containing either 1000 ppm (HZ), 50 ppm (NZ), or 1 ppm zinc (LZ) starting at 30 days of age. Non-diabetes-prone rats were fed NZ and designated as con trols (NORM), Beginning at 60 days, the rats were checked for glycosur ia and, if positive, were given an ip glucose tolerance test (IPGTT), All remaining animals underwent an IPGTT at 100 days and were sacrific ed, At 90 days of age HZ rats had a lower incidence of diabetes (19%) than NZ (53%) or LZ (44%) animals (P < 0.015).,By age 100 days, for th e HZ group, there was a 60% reduction in the number of expected overt diabetic rats, HZ animals also had higher concentrations of both pancr eatic and serum insulin and exhibited lower serum glucose and triglyce rides. Immunohistochemistry of HZ rats was clearly different from NZ r ats and showed evidence of nearly normal pancreatic endocrine activity . Data indicate that dietary treatment of diabetes-prone BE Wistar rat s with zinc appears to be an effective approach for delaying or preven ting the onset of diabetes in genetically predisposed rodents. This fi nding may suggest further experimental studies regarding dietary means for preservation of pancreatic function. (C) 1998 Academic Press.