APStracts 2:0099R, 1995.

Sulfate-oxalate exchange by lobster hepatopancreatic basolateral membrane vesicles. Gerencser, George A., Mark A. Cattey, and Gregory A. Ahearn. Department of Physiology, College of Medicine, University of Florida, Gainesville, FL. 32610. Department of Zoology, 2538 The Mall, University of Hawaii at Manoa, Honolulu, Hawaii 96822

APStracts 2:0099R, 1995.

Purified basolateral membrane vesicles (BLMV) were prepared from lobster hepatopancreas by osmotic disruption and discontinuous sucrose gradient centrifugation. 35[S]ulfate uptake was stimulated by 10 mM intravesicular oxalate when compared to gluconate loaded vesicles. Sulfate-oxalate exchange was not affected by transmembrane valinomycin-induced potassium diffusion potentials (inside-negative or inside-positive) suggesting electroneutral anion transport. Sulfate uptake was not stimulated by the similar carboxylic anions: formate, succinate, oxaloacetate or ketoglutarate. Sulfate influx occurred by at least one saturable Michaelis-Menten carrier system (apparent Km = 6.0 +/- 1.7 mM and Jmax = 382.3 +/- 37.0 pmol/mg protein/7 s. Sulfate-oxalate exchange was significantly reduced by the anion antiport inhibitors DIDS and SITS, but not affected by bumetanide or furosemide. The possible physiological role of this exchange mechanism in anion-sulfate transport across the crustacean hepatopancreas is discussed.

Received 10 June 1992; accepted in final form 23 March 1995.
APS Manuscript Number R258-2.
Article publication pending Am. J. Physiol. (Regulatory Integrative
Comp. Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 19 April 1995.