Changes in Renal Tubular Transport Maxima Associated With Renal Vasodilatation

Abstract

Renal tubular transport maxima, both reabsorptive and excretory, were in a series of human subjects under the condition of renal hyperemia. During the rapid administration of 0.5g. of amino-phyllin, TmpAH increased significantly from a mean control value of 61.2 mg./min. to 76.4 mg./min. in a group of 10 subjects. During the rapid administration of 0.5g. of aminophyllin in a 2d series of 12 subjects, TmG increased significantly from a control mean of 281 mg./min. to 326 mg./min. Following the intraven. administration of 50 million killed typhoid organisms to a 3d group of 8 subjects, a statistically significant increment in TmpAH was noted. The data are compatible with the existence of some nephrons in the human kidney which are not measurably perfused under the standard conditions of a renal function test and whose presence is revealed only during renal vasodilation.