Renal function and the renin-angiotensin system in the isolated perfused kidney

Abstract

The pattern of renal function in an isolated blood-perfused pump oxygenator kidney preparationis described. This consisted of an initial phase during which renal hemodynamic and functional parameters were maintained at relatively constant levels only slightly lower than those measured in intact kidneys. This was followed, after a variable time interval, by a 2nd phase during which renal function was much less efficient and less adaptive to alterations in the perfusion system. The most characteristic feature of the isolated kidney during the latter stage of perfusion was a reduction of intrarenal vascular resistance. Periodic measurements of renin and renin substrate in the blood per-fusate revealed elevated renin and depressed renin substrate concentrations during the latter stages of perfusion. A possible relationship between alterations in the renin-angiotensin system and abnormal renal function in the late stages of isolated kidney perfusion is considered.