Facilitation by serum albumin of renal tubular secretion of organic anions.
Details
Serval ID
serval:BIB_63BC75F2B1BF
Type
Article: article from journal or magazin.
Collection
Publications
Institution
Title
Facilitation by serum albumin of renal tubular secretion of organic anions.
Journal
American Journal of Physiology
ISSN
0002-9513
Publication state
Published
Issued date
03/1989
Peer-reviewed
Oui
Volume
256
Number
3 Pt 2
Pages
F475-484
Language
english
Abstract
The role of albumin in tubular secretion of the organic anions p-aminohippurate (PAH, 21% albumin-bound at 1 microM) and methotrexate (MTX, 55% bound at 1 microM), and of the organic cation N1-methylnicotinamide (NMN, not bound), was investigated in isolated rabbit S2 proximal tubules. PAH or MTX secretory rates were low in the absence of colloids or in the presence of 1 g/dl dextran 40, and were reversibly two- to sevenfold stimulated by either 1 g/dl bovine (BSA, either regular, defatted, and/or dialyzed) or rabbit serum albumin, or by dialyzed native rabbit plasma. NMN secretion was not stimulated by either dextran or albumin. Luminal BSA had no effect, but stimulation of PAH secretion was observed when albumin was present in both lumen and bath. This secretion was BSA concentration-dependent up to a 1 g/dl BSA. Saturation experiments suggested that 1 g/dl BSA may increase PAH apparent affinity for secretion, with no change in its maximum velocity. Albumin appears therefore to facilitate organic anion proximal secretion by an effect unrelated to oncotic pressure or to the extent of organic anion binding.
Keywords
Animals, Dextrans/pharmacology, Kidney Tubules, Proximal/drug effects, Kidney Tubules, Proximal/physiology, Kinetics, Methotrexate/metabolism, Niacinamide/analogs & derivatives, Niacinamide/metabolism, Protein Binding, Rabbits, Serum Albumin, Bovine/metabolism, p-Aminohippuric Acid/diagnostic use, p-Aminohippuric Acid/metabolism
Pubmed
Web of science
Create date
17/07/2009 16:26
Last modification date
20/08/2019 14:20