Xenon-133 washout for measuring intrarenal blood flow in the micropuncture rat

Repeated 133Xe-washout curves of renal blood flow and distribution can be obtained easily if retrograde femoral artery catheterization of the aorta and a lead kidney cup are added to the standard micropuncture (MP) preparation of the rat. Each such study need be only 6 min. Mean cortical blood flow distribution (Ao1) of 13 micropuncture rats (36 studies) was 69 percent (SE = 1.7, SD = 10). Individual rats were reproducible in any one study with an SD of less than 6; however, the range was 47 to 81 percent. Mean outer cortical flow (F1) was 3.5 ml/min per g (SE = 0.4, SD = 1.5). Autoradiographs and postnephrectomy studies verified the distribution and source of the radioactivity. Mean total blood flow (Fo) correlated well with total flow determined by the clearance of PAH or an electromagnetic flow probe. Studies in dogs corroborated the reproducibility of Ao1 in any one series of washout studies and significant variation in Ao1 between animals or studies of the same dog kidney on different days. (U.S.)