AJP - Regulatory, Integrative and Comparative Physiology, Vol 252, Issue 1 153-R159, Copyright © 1987 by American Physiological Society
Organic cation secretion by Cancer borealis urinary bladder
D. S. Miller and C. W. Holliday
In the crab, Cancer borealis, initial clearance studies showed a potent
renal excretory system for the model organic cation, tetraethylammonium
(TEA). TEA clearance averaged 145 +/- 32 ml/day, which was 18 times the
paired polyethylene glycol clearance. TEA uptake by slices of urinary
bladder was concentrative, saturable, inhibitable by N1-methylnicotinamide
chloride, and dependent on glycolytic, but not oxidative, metabolism. When
mounted in flux chambers, bladders exhibited a large net secretory flux.
For 0.1 mM TEA, the ratio of secretory to reabsorptive fluxes was 65.
Urinary bladders from another crab, Cancer irroratus, and a lobster,
Homarus americanus, also exhibited net TEA secretion. In C. borealis
bladder, secretory transport was concentrative, saturable, and nearly
abolished by addition of 1 mM quinine to the serosal bath. Reabsorptive
transport was not concentrative and was not reduced by luminal quinine. The
data are consistent with a secretory pathway that is transcellular and
mediated by carriers at both the serosal and luminal membranes.
