49 A Transport System in Mammalian Kidney with Preference For β-Amino Compounds
49 A Transport System in Mammalian Kidney with Preference For β-Amino Compounds
复制标题
49 哺乳动物肾脏中偏爱 β-氨基化合物的转运系统
作者：
H. Goldman;C. Scriver
An absorptive transport system in human kidney common to the naturally occurring β-amino compounds, β-alanine, β-aminoisobutyric acid and taurine has been proposed on the basis of evidence found in the aminoacidopathy, hyper-β-alaninemia (New. Engl.J. Med. 274: 635 [1966]). The proposal has been investigated further in the rat. Absorptive renal transport (lumen to cell) was selected for by using probenicid (200 mg/kg) to block tubular secretion of D-(-)βAIB. By means of intraperitoneal injection, the plasma concentration of β-amino compounds was raised; urinary excretion of amino acids was analyzed by chromatographic methods. Mutual competitive inhibition of absorptive transport was observed between βala, βAIB and Tau. βala had the greatest inhibitory effect, and Tau the least. β-amino compounds had no significant effect on the excretion of α-amino acids when the latter were present at either high or normal plasma concentrations; conversely, α-amino acids did not inhibit β-amino absorption. A common transport system for β-amino compounds operative at high concentrations, and whose order of substrate affinity is βala > L-βAIB> Tau, is thus demonstrable in mammalian kidney. (Supported by M.R.C. Grant, MA-1894, and N.I.H. Grant, AM-05117). (SPR)
