Impaired glucose tolerance in the R6/1 transgenic mouse model of Huntington's disease

Area of Science:

• Neuroscience
• Endocrinology
• Genetics

Background:

• A potential link between Huntington's disease (HD) and diabetes mellitus (DM) has been suggested but not fully characterized.
• Transgenic mouse models offer insights into HD pathogenesis and associated conditions.

Purpose of the Study:

• To investigate glucose metabolism and pancreatic islet function in the R6/1 mouse model of Huntington's disease.
• To explore the presence of the Huntington's disease gene product in pancreatic cells.

Main Methods:

• Glucose tolerance tests and insulin level measurements in R6/1 and wild-type mice.
• Assessment of beta cell volume and apoptosis in pancreatic islets.
• Immunohistochemical analysis for the presence of huntingtin protein.

Main Results:

• R6/1 mice exhibited impaired glucose tolerance and higher blood glucose levels compared to wild-type controls.
• While insulin sensitivity was normal, R6/1 mice showed reduced beta cell volume and increased plasma insulin levels.
• The Huntington's disease gene product, huntingtin, was detected in both alpha- and beta-cells of R6/1 mouse islets.

Conclusions:

• The R6/1 mouse model displays key signs of glucose intolerance and pancreatic beta cell dysfunction, independent of apoptosis.
• The presence of huntingtin in pancreatic islet cells suggests a potential molecular link between Huntington's disease and diabetes mellitus.
• Understanding these mechanisms could illuminate pathogenic pathways common to neurodegenerative disorders and diabetes.