Keywords: تومورهای سلولی جزیره; ICTs; islet cell tumors; STZ; streptozotocin; NA; nicotinamide; PNETs; pancreatic neuroendocrine tumors; PNECs; pancreatic neuroendocrine carcinomas; PCNA; proliferating cell nuclear antigen; Adrenal; Diabetes; Glucose; Insulin; Kidney; Liver;