Glomerular filtration rate in early experimental diabetes

Area of Science:

• Nephrology
• Nuclear Medicine
• Pharmacology

Background:

• Glomerular filtration rate (GFR) is a key indicator of kidney function.
• Accurate and reproducible GFR measurement is crucial for studying kidney disease, particularly in experimental models.
• Existing methods for GFR measurement can be invasive or complex.

Purpose of the Study:

• To develop and validate a noninvasive single-injection technique for serial GFR measurement in rats using technetium-99m DTPA.
• To assess the impact of diabetes, insulin treatment, high protein intake, genetic hypertension, and ACE inhibition on GFR in rats.

Main Methods:

• Development of a noninvasive GFR measurement technique using technetium-99m DTPA in rats.
• Validation of the technique against Cr51 EDTA infusion.
• Serial GFR measurements in diabetic and control rats over 4 weeks.
• Assessment of factors including insulin treatment, protein intake, genetic hypertension, and ACE inhibition (ramipril).

Main Results:

• The technetium-99m DTPA method showed good correlation with Cr51 EDTA (R=0.95) and a coefficient of variation of 8.4%.
• Diabetes was associated with a significantly increased GFR when corrected for body weight (p < 0.001).
• Insulin treatment normalized GFR/kg in diabetic rats, while high protein intake and ACE inhibition had minimal effects on GFR in this model.

Conclusions:

• Serial GFR measurement in diabetic rats using technetium-99m DTPA is accurate and reproducible.
• Experimental diabetes leads to increased GFR, which is influenced by insulin treatment.
• Factors like genetic hypertension, high protein intake, and ACE inhibition demonstrate limited impact on GFR in this experimental diabetes model.