Cycloleucine (1-amino-cyclopentane carboxylic acid): tubular reabsorption and inhibitory effect on amino acid transport in the rat kidney. (Microperfusion experiments).
Renal tubular reabsorption of cycloleucine (1-amino-cyclopentane carboxylic acid) was studied in vivo et situ by continuous microperfusion of single proximal tubules of the rat. The results show: a) cycloleucine is reabsorbed rapidly compared with other amino acids b) this reabsorption is saturable and can be inhibited by oligomycin c) cycloleucine inhibits tubular reabsorption of L-arginine, glycine, and of L-phenylalanine. Mutual reciprocal inhibition occurs only with L-phenylalanine (and perhaps also with glycine). A maximal possible permeability coefficient for cycloleucine (less than 6 times 10--5 cm times sec--1) was calculated. Assuming simple 2-parameter kinetics, Vmax and Km for tubular reabsorption of cycloleucine were estimated. It can be concluded from the present results that cycloleucine is reabsorbed by a mechanism that transports L-phenylalanine, but not by the system shared by dibasic amino acids.
D000042:Absorption; D000596:Amino Acids / Q000378:metabolism*; D000818:Animals; D000970:Antineoplastic Agents / Q000378:metabolism*; D001120:Arginine / Q000378:metabolism; D001692:Biological Transport / Q000187:drug effects; D002463:Cell Membrane Permeability; D003517:Cyclopentanes / Q000031:analogs & derivatives* / Q000378:metabolism / Q000494:pharmacology; D005998:Glycine / Q000378:metabolism; D007687:Kidney Tubules, Proximal / Q000378:metabolism*; D007700:Kinetics; D008297:Male; D009840:Oligomycins / Q000494:pharmacology; D010477:Perfusion; D010649:Phenylalanine / Q000378:metabolism; D051381:Rats
D000596:Amino Acids; D000970:Antineoplastic Agents; D003517:Cyclopentanes; D009840:Oligomycins; D010649:Phenylalanine; D001120:Arginine; D005998:Glycine