Measurement of glomerular filtration rate in anesthetized and conscious rhesus monkeys (Macaca mulatta).

Objective—To validate a method to assess glomerular filtration rate (GFR) in conscious monkeys via transcutaneous radiation detection after IV injection of technetium Tc 99m pentatate(99mTc-DTPA). Animals—4 healthy rhesus monkeys. Procedures—On day 1, each monkey was anesthetized, lothalamate sodium I 125 (125l-iothalamate) was administered via continuous rate infusion (0.0037 MBq/min); blood and urine samples were obtained for determination of 125l-iothalamate plasma clearance variables and estimation of GFR. One dose of 99mTc-DTPA (74 MBq/kg, IV) was also administered during the 125l-iothalamate plasma clearance test, and transcutaneous measurements of technetium 99m-emitted radiation were obtained by use of an ambulatory renal monitor (ARM) applied to a brachium of each monkey. Determination of GFR by use of the ARM was repeated on days 8 and 45 in the same monkeys without anesthesia. Results—Sensitivity, accuracy, and precision of the 2 methods were similar. By use of the ARM, GFR determined by use of...