Intrarenal Distribution of Nutrient Blood Flow Determined with Krypton ⁸⁵ in the Unanesthetized Dog

Abstract

A method has been described for the measurement, by means of Kr 85 , of intrarenal nutrient blood flow distribution in the unanesthetized dog. Injection of the isotope into the renal artery is followed by a multi-exponential disappearance curve which can be obtained by external monitoring with a scintillation detector. In acute experiments autoradiographs have demonstrated that the first exponential component represents cortical blood flow; the second, outer medullary blood flow : the third, inner medullary blood flow; and the fourth, hilar and perirenal fat blood flow. The average cortical blood flow in 65 experiments in five kidneys of four nnanesthetized dogs was 472 ml/100 g/min, the outer medullary 132 ml/100 g/min, and the inner medullary 17 ml/100 g/min. Eighty per cent of the radioactivity was distributed initially to the cortex, 16% to the outer medulla, and 2% to the inner medulla. The hilar and perirenal fat, which receives approximately 2% of the initial radioactivity, was estimated to have a flow rate of 21 ml/100 g/min. In addition, a method for the rapid determination of serial cortical blood flow rates has been described. The importance of these findings has been discussed with reference to the anatomy of the kidney, and to the countercurrent concept as it applies to passive reabsorption of lipid soluble substances, and to the maintenance of an osmotic gradient.

Intrarenal Blood Flow Distribution in Canine Puppies

“…In the remaining puppies and in the adult dogs, at the time of the study, a 27-gauge butterfly needle was inserted into the right renal artery for xenon injection. The animals were deprived of water and fasted for 12-16 hr prior to the procedure to insure low urine flow [51] and anesthetized with pentobarbital, 30 mg/kg, administered intravenously. Aortic blood pressure was monitored from a catheter inserted through the femoral artery, using a strain gauge transducer [55] connected to a recorder [56].…”

“…Intrarenal blood flow distribution (IRBF) has also been measured by the washout of radioactive noble gases [28,51]. This technique, although also imperfect, appears to be reliable for measuring flow distribution to outer regions of the kidney and permits repeated studies in the same animal [28].…”

Intrarenal Blood Flow in Children with Normal Kidneys and Congenital Heart Disease: Changes Attributable to Angiography

“…Physiologically, the 1"Xe technique is the only clinically available method capable of providing data relating to intracortical blood flow patterns. Moreover, the units of measurement of flow, in milliliters per minute per 100 g [54], and fraction of total flow, as a percentage [54], are independent of body size. This permits direct comparison of data obtained in children of various ages.…”

Renal function tests: what do they mean? A review of renal anatomy, biochemistry, and physiology.

“…The straight lines indicate that this curve can be resolved into multiple components, indicating three or four blood flow compartments. Autoradiographic analysis by Barger and others (5,6) permitted assignment of these kinetic compartments to the anatomical entities mentioned above. As much as 80-85% of total renal blood flow can be associated with cortical regions; 10-12% is thought to perfuse the inner medulla, and the remainder of the total blood flow distributes to other aspects of the kidney.…”