Renal blood flow during ureteral obstruction measured with 133Xe wash out, 86Rb uptake techniques and with an electromagnetic flowmeter.

In moderate mannitol diuresis in the dog the ratio RBF-86Rb uptake/RBF-electromagnetic flowmeter decreased during ureteral obstruction from 0.923 - 0.705. In the same animals the ratio RBF-133Xe wash-out/RBF-electromagnetic flowmeter increased from 0.932 - 1.365. With the rubidium technique a significant redistribution of intrarenal blood flow was observed. No similar flow changes were seen with the 133Xe wash-out technique. The two methods do not measure during ureteral obstruction the true RBF. The change of 86Rb uptake by the individual segments of renal tissue is not an unequivocal proof for the intrarenal redistribution of blood flow, but this possibility cannot be definitely excluded.