Renal extraction ratios for 51Cr-EDTA, PAH, and glucose in early insulin-dependent diabetic patients.

Renal clearances and extraction ratios for 51Cr-EDTA and PAH were studied in six young patients with insulin-dependent diabetes. The duration of the disease was 1 to 4 years, and no patient had signs of diabetic complications. Catheterization of the right renal vein and the left brachial artery was performed. The extraction ratios for 51Cr-EDTA, PAH, and glucose were determined at two different levels of blood glucose. Clearance for 51Cr-EDTA was increased by 9.7% and for PAH by 8.5% compared to normal control subjects while the extraction ratios for 51Cr-EDTA and PAH were normal. Extraction ratio for glucose was very low. There was no correlation between the individual HbA1 values and the clearances for 51Cr-EDTA and PAH. Extraction ratios for these substances were not influenced by acute changes in blood glucose level. The normal PAH extraction ratio indicates that PAH clearance is a reliable estimate of RPF in early insulin-dependent diabetes.