|
|
||||||||
AJP - Renal Physiology, Vol 242, Issue 5 484-F490, Copyright © 1982 by American Physiological Society
ARTICLES |
W. M. Williams and K. C. Huang
The renal excretion of folic acid and methotrexate (MTX) was investigated in pentobarbital-anesthetized cynomolgus, rhesus, and AFrican green monkeys by standard clearance and stop-flow techniques. The renal clearance of folic acid was below inulin clearance at all plasma concentrations studied; the (U/P)folic/(U/P)In ratio increased from 0.26 at a concentration of 0.03 mM to a plateau value of 0.9 at concentrations above 0.2 mM, indicating net reabsorption by a saturable system. In stop-flow experiments, base-line (U/P)folic/(U/P)In ratios during free-flow periods were below 1.0, but increased by twofold in stop-flow samples derived from the proximal tubule, indicating net secretion during stopped flow. The stop-flow pattern of MTX excretion was similar, except the base-line flow pattern of MTX excretion was similar, except the base-line (U/P)MTX/(U/P)In ratio exceeded 1.0, indicating net secretion during both free-flow and stopped-flow periods. Secretion of both compounds was inhibited by p-aminohippuric acid and other organic acids but not by L-glutamic acid. It is concluded that folic acid is transported bidirectionally, while evidence was obtained only for secretion of MTX.
This article has been cited by other articles:
![]() |
A. Qiu, S. H. Min, M. Jansen, U. Malhotra, E. Tsai, D. C. Cabelof, L. H. Matherly, R. Zhao, M. H. Akabas, and I. D. Goldman Rodent intestinal folate transporters (SLC46A1): secondary structure, functional properties, and response to dietary folate restriction Am J Physiol Cell Physiol, November 1, 2007; 293(5): C1669 - C1678. [Abstract] [Full Text] [PDF] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |