Hyperinsulinemic-euglycemic clamps in conscious, unrestrained mice

Area of Science:

• Metabolic Research
• Physiology
• Animal Models

Background:

• Type 2 diabetes involves impaired insulin action.
• The hyperinsulinemic-euglycemic clamp is the gold standard for assessing insulin action in vivo.
• Standard clamp methods can vary, affecting results.

Purpose of the Study:

• To present a refined protocol for performing insulin clamps in conscious, unrestrained mice.
• To detail a unique two-catheter system for improved blood sampling and reduced animal stress.
• To provide guidelines for assessing tissue-specific insulin action and presenting results.

Main Methods:

• Utilized a two-catheter system: one for infusions (jugular vein), one for blood sampling (carotid artery).
• Employed isotopic tracers (2[(14)C]deoxyglucose and [3-(3)H]glucose) to measure tissue-specific glucose uptake and endogenous glucose production.
• Developed a protocol for conscious, unrestrained mice to minimize stress and improve data reliability.

Main Results:

• The described method allows for accurate assessment of whole-body insulin action (glucose infusion rate - GIR).
• Tissue-specific glucose uptake and insulin's effect on endogenous glucose production can be evaluated.
• The arterial catheter blood sampling method is less stressful than tail-tip sampling.

Conclusions:

• The presented insulin clamp protocol enhances accuracy and reproducibility in mouse models of metabolic disease.
• This refined technique contributes to significant advances in diabetes research.
• Minimizing animal stress during experiments is crucial for reliable metabolic phenotyping.