Abstract
The renal proximal tubule is the site of active secretion of a diverse array of organic cations and bases (collectively, OCs). The basolateral entry step in transtubule OC transport involves an electrogenic facilitated diffusion process. OC exit into the tubule lumen is the active step in secretion and involves the carrier-mediated exchange of OC for H+. The specificity of these two processes is influenced less by steric characteristics of substrates than by their chemical lipophilicity, with both transporters displaying an increasing affinity for OCs of increasing lipophilicity. Several additional OC transporters exist within each membrane and the concerted activity of these processes permits the proximal tubule to effect the secretion of most OCs, and the selective reabsorption of others, and provides the tubule with a degree of “redundancy” in the means available for secreting potentially toxic xenobiotic compounds from the body.
Original language | English (US) |
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Pages (from-to) | 112-122 |
Number of pages | 11 |
Journal | Cellular Physiology and Biochemistry |
Volume | 6 |
Issue number | 1-2 |
DOIs | |
State | Published - Sep 4 1996 |
Keywords
- Basolateral membrane
- Brush-border membrane
- Kidney
- Organic cation transport
- Proximal tubule
ASJC Scopus subject areas
- Physiology