Reduced beta cell mass in pancreatic islets (PI) of Goto-Kakizaki (GK) rats is frequently observed in this diabetic model, but knowledge on delta cells is scarce. Aiming to compare delta cell physiology/pathology of GK to Wistar rats, we found that delta cell number increased over time as did somatostatin mRNA and delta cells distribution in PI is different in GK rats. Subtle changes in 6-week-old GK rats were found. With maturation and aging of GK rats, disturbed cytoarchitecture occurred with irregular beta cells accompanied by delta cell hyperplasia and loss of pancreatic polypeptide (PPY) positivity. Unlike the constant glucose-stimulation index for insulin PI release in Wistar rats, this index declined with GK age, whereas for somatostatin it increased with age. A decrease of GK rat PPY serum levels was found. GK rat body weight decreased with increasing hyperglycemia. Somatostatin analog octreotide completely blocked insulin secretion, impaired proliferation at low autocrine insulin, and decreased PPY secretion and mitochondrial DNA in INS-1E cells. In conclusion, in GK rats PI, significant local delta cell hyperplasia and suspected paracrine effect of somatostatin diminish beta cell viability and contribute to the deterioration of beta cell mass. Altered PPY-secreting cells distribution amends another component of GK PI's pathophysiology.

• MeSH
• Insulin Antagonists pharmacology   MeSH
• Insulin-Secreting Cells drug effects   metabolism   pathology   MeSH
• Somatostatin-Secreting Cells drug effects   metabolism   pathology   MeSH
• Diabetes Mellitus, Type 2 blood   metabolism   pathology   MeSH
• Hyperplasia MeSH
• Immunohistochemistry MeSH
• Rats, Inbred Strains MeSH
• Insulin metabolism   MeSH
• Insulin Resistance * MeSH
• RNA, Messenger metabolism   MeSH
• Cell Line, Tumor MeSH
• Octreotide pharmacology   MeSH
• Pancreatic Polypeptide antagonists & inhibitors   genetics   metabolism   MeSH
• Rats, Wistar MeSH
• Cell Proliferation drug effects   MeSH
• Insulin Secretion MeSH
• Somatostatin antagonists & inhibitors   genetics   metabolism   MeSH
• Aging * MeSH
• Cell Survival drug effects   MeSH
• Gene Expression Regulation, Developmental MeSH
• Animals MeSH
• Check Tag
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Insulin Antagonists MeSH
• Insulin MeSH
• RNA, Messenger MeSH
• Octreotide MeSH
• Pancreatic Polypeptide MeSH
• Somatostatin MeSH