Endocrine pancreas in the postnatal offspring of alloxan diabetic rats

This study was conducted to investigate the morphological changes in the postnatal pancreatic islets in offspring of diabetic rats. Diabetes was induced in female Sprague Dawley rats by intravenous injection of alloxan (40 mg/kg). After 1 week, rats with blood sugar above 270 mg% were bred and watched until spontaneous delivery occurred. Litters in the following age groups were sacrificed by decapitation, 0, 8, 24, 72 and 168 h, and compared with their controls. Blood sugar levels were significantly higher in the neonates of diabetic mothers immediately after delivery compared to the control, then became normal after 8 h. Islets of the offspring of the diabetics at birth showed weak positive staining for insulin using immunocytochemical techniques. By 72 h some cells showed immunopositive staining similar to the control, while at 168 h all the beta (B) cells were stained normally. Beta cells of the islets from the diabetic series at birth were almost completely degranulated except for scattered granules toward the periphery. Their cytoplasm exhibited glycogen and lipid accumulations. Cells also showed signs of hyperfunction in the form of an extensive endoplasmic reticulum and well-developed Golgi complex with distended Golgi cisternae. At 8 h postnatally the population of pale secretory granules was markedly increased. The changes described at birth persisted at 24 h and, to a lesser extent, 72 h after delivery. At the age of 1 week, the beta cells appeared to be normal.