Glucose disappearance rate in rhesus monkeys: Some technical considerations

Area of Science:

• Endocrinology
• Metabolic Research
• Primate Studies

Background:

• The intravenous glucose tolerance test (IVGTT) is vital for diagnosing diabetes mellitus.
• Calculating the glucose disappearance rate (K_G) indicates glucose tolerance.
• Lack of standardization in rhesus monkey IVGTTs hinders result interpretation.

Purpose of the Study:

• To establish a standardized method for calculating K_G in rhesus monkeys using IVGTT.
• To identify optimal time points and formulas for accurate K_G calculation.
• To improve consistency and reliability of glucose tolerance assessment in research primates.

Main Methods:

• Analysis of 48 IVGTTs from 33 male rhesus monkeys with varying glucose tolerance.
• Testing various formulas and time point pairs for K_G calculation.
• Utilizing regression analysis on log_e-transformed plasma glucose levels.

Main Results:

• Plasma glucose levels best fit a straight line between 5 and 20 minutes post-injection (R² = 0.97 ± 0.005).
• Early time points (before 5 min) yielded inflated K_G values.
• Late time points (after 30 min) sometimes resulted in invalid K_G as glucose levels returned to baseline.

Conclusions:

• The 5- and 20-minute time points are optimal for calculating K_G in rhesus monkeys.
• This method accurately reflects glucose uptake, requires minimal sampling time, and simplifies calculation.
• Standardized K_G calculation enhances the diagnostic utility of IVGTT in primate research.