Sulfate-chloride exchange by lobster hepatopancreas is regulated by pH-sensitive modifier sites
- Univ. of Hawaii, Honolulu (United States) Univ. of Florida, Gainesville (United States)
{sup 35}SO{sub 4}{sup 2{minus}} uptake by Atlantic lobster (Homarus americanus) hepatopancreatic epithelial brush border membrane vesicles (BBMV) was stimulated by internal Cl{sup {minus}}, but not internal HCO{sub 3}{sup {minus}}, or external Na{sup +}. Sulfate-chloride exchange was stimulated by inside positive, and inhibited by inside negative, trans-membrane K diffusion potentials. {sup 35}SO{sub 4}{sup 2{minus}}-Cl{sup {minus}} exchange was strongly inhibited by 4,4{prime} diisothiocyanostilbene-2,2{prime}-disulfonic acid (DIDS), 4-acetamido-4{prime}-isotheocynaostilbene-2,2{prime}-disulfonic acid, (SITS), and thiosulfate. Chloride, bicarbonate, furosamide, and bumetanide slightly, yet significantly, cis-inhibited {sup 35}SO{sub 4}{sup 2{minus}}-Cl{sup {minus}} exchange. Altering bilateral pH from 8.0 to 5.4 stimulated {sup 35}SO{sub 4}{sup 2{minus}}-Cl{sup {minus}} exchange when vesicles were loaded with Cl{sup {minus}}, but reduced bilateral pH alone or the presence of pH gradients did not affect {sup 35}SO{sub 4}{sup 2{minus}} transport in the absence of internal Cl{sup {minus}}. {sup 36}Cl uptake into SO{sub 4}{sup 2{minus}}-loaded BBMV was stimulated by an internal negative membrane potential and inhibited when the interior was electrically positive. A model is proposed which suggests that SO{sub 4}{sup 2{minus}}-Cl{sup {minus}} exchange is regulated by internal and external pH-sensitive modifier sites on the anion antiporter and by coupling to the electrogenic 2 Na{sup +}/1 H{sup +} antiporter and by coupling to the electrogenic 2 Na{sup +}/1 H{sup +} antiporter on the same membrane.
- OSTI ID:
- 5173717
- Report Number(s):
- CONF-9104107-; CODEN: FAJOE
- Journal Information:
- FASEB Journal (Federation of American Societies for Experimental Biology); (United States), Vol. 5:5; Conference: 75. annual meeting of the Federation of American Societies for Experimental Biology (FASEB), Atlanta, GA (United States), 21-25 Apr 1991; ISSN 0892-6638
- Country of Publication:
- United States
- Language:
- English
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CHLORIDES
METABOLISM
SULFATES
EPITHELIUM
ION EXCHANGE
LIVER
LOBSTERS
MATHEMATICAL MODELS
MEMBRANE TRANSPORT
PANCREAS
PH VALUE
SULFUR 35
TRACER TECHNIQUES
ANIMAL TISSUES
ANIMALS
AQUATIC ORGANISMS
ARTHROPODS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BODY
CHLORINE COMPOUNDS
CRUSTACEANS
DAYS LIVING RADIOISOTOPES
DECAPODS
DIGESTIVE SYSTEM
ENDOCRINE GLANDS
EVEN-ODD NUCLEI
GLANDS
HALIDES
HALOGEN COMPOUNDS
INVERTEBRATES
ISOTOPE APPLICATIONS
ISOTOPES
LIGHT NUCLEI
NUCLEI
ORGANS
OXYGEN COMPOUNDS
RADIOISOTOPES
SULFUR COMPOUNDS
SULFUR ISOTOPES
TISSUES
560300* - Chemicals Metabolism & Toxicology