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Title: Modulation of cytosolic free calcium levels by extracellular phosphate and lanthanum

Abstract

The effects of extracellular phosphate and lanthanum on cytosolic free Ca/sup 2 +/ ((Ca/sup 2 +/)/sub i/) levels were studied in isolated rat pancreatic acini. In the presence of 1.28 mM Ca/sup 2 +/ and 1.0 mM phosphate, the mean resting (Ca/sup 2 +/)/sub i/ level was 120 nM. Omission of phosphate from incubation medium significantly lowered this value to 94 nM. The gastrointestinal hormone cholecystokinin octapeptide (CCK-8) rapidly enhanced both (Ca/sup 2 +/)/sub i/ levels and /sup 45/Ca/sup 2 +/ efflux, irrespective of the presence or absence of phosphate. Lanthanum (0.1 mM), a compound known to block transmembrane Ca/sup 2 +/ fluxes, attenuated both actions of CCK-8, but only in the absence of extracellular phosphate. There was a concomitant decrease in amylase secretion induced by 0.1 nM CCK-8 but not by 10 nM CCK-8, without a significant change in cellular ATP levels. The inhibitory actions of lanthanum on CCK-8-stimulated (Ca/sup 2 +/)/sub i/ levels were very rapid and were mimicked only by prolonged incubation of acini in Ca/sup 2 +/-free medium supplemented with EGTA. Omission of phosphate from incubation medium also lowered basal (Ca/sup 2 +/)/sub i/ levels in IM-9 lymphocytes. These findings suggest that extracellular phosphate may modulatemore » resting (Ca/sup 2 +/)/sub i/ levels in pancreatic acini and other cell types and that mobilization of intracellular Ca/sup 2 +/ may partly depend on the availability of a lanthanum-sensitive pool of cell-surface Ca/sup 2 +/ that is not readily removed by EGTA.« less

Authors:
;
Publication Date:
Research Org.:
Univ. of Arizona, Tucson
OSTI Identifier:
6372501
Resource Type:
Journal Article
Resource Relation:
Journal Name: Proc. Natl. Acad. Sci. U.S.A.; (United States); Journal Volume: 84:5
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES; 63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.; CALCIUM 45; MEMBRANE TRANSPORT; LANTHANUM; BIOCHEMISTRY; SODIUM PHOSPHATES; AMYLASE; CALCIUM COMPOUNDS; CATIONS; LYMPHOCYTES; METABOLIC DISEASES; PANCREAS; RATS; SODIUM CHLORIDES; ALKALI METAL COMPOUNDS; ALKALINE EARTH ISOTOPES; ALKALINE EARTH METAL COMPOUNDS; ANIMAL CELLS; ANIMALS; BETA DECAY RADIOISOTOPES; BETA-MINUS DECAY RADIOISOTOPES; BIOLOGICAL MATERIALS; BLOOD; BLOOD CELLS; BODY; BODY FLUIDS; CALCIUM ISOTOPES; CHARGED PARTICLES; CHEMISTRY; CHLORIDES; CHLORINE COMPOUNDS; CONNECTIVE TISSUE CELLS; DAYS LIVING RADIOISOTOPES; DIGESTIVE SYSTEM; DISEASES; ELEMENTS; ENDOCRINE GLANDS; ENZYMES; EVEN-ODD NUCLEI; GLANDS; GLYCOSYL HYDROLASES; HALIDES; HALOGEN COMPOUNDS; HYDROLASES; INTERMEDIATE MASS NUCLEI; IONS; ISOTOPES; LEUKOCYTES; MAMMALS; MATERIALS; METALS; NUCLEI; O-GLYCOSYL HYDROLASES; ORGANS; OXYGEN COMPOUNDS; PHOSPHATES; PHOSPHORUS COMPOUNDS; RADIOISOTOPES; RARE EARTHS; RODENTS; SODIUM COMPOUNDS; SOMATIC CELLS; VERTEBRATES; 550301* - Cytology- Tracer Techniques; 560300 - Chemicals Metabolism & Toxicology

Citation Formats

Korc, M., and Schoeni, M.H.. Modulation of cytosolic free calcium levels by extracellular phosphate and lanthanum. United States: N. p., 1987. Web. doi:10.1073/pnas.84.5.1282.
Korc, M., & Schoeni, M.H.. Modulation of cytosolic free calcium levels by extracellular phosphate and lanthanum. United States. doi:10.1073/pnas.84.5.1282.
Korc, M., and Schoeni, M.H.. Sun . "Modulation of cytosolic free calcium levels by extracellular phosphate and lanthanum". United States. doi:10.1073/pnas.84.5.1282.
@article{osti_6372501,
title = {Modulation of cytosolic free calcium levels by extracellular phosphate and lanthanum},
author = {Korc, M. and Schoeni, M.H.},
abstractNote = {The effects of extracellular phosphate and lanthanum on cytosolic free Ca/sup 2 +/ ((Ca/sup 2 +/)/sub i/) levels were studied in isolated rat pancreatic acini. In the presence of 1.28 mM Ca/sup 2 +/ and 1.0 mM phosphate, the mean resting (Ca/sup 2 +/)/sub i/ level was 120 nM. Omission of phosphate from incubation medium significantly lowered this value to 94 nM. The gastrointestinal hormone cholecystokinin octapeptide (CCK-8) rapidly enhanced both (Ca/sup 2 +/)/sub i/ levels and /sup 45/Ca/sup 2 +/ efflux, irrespective of the presence or absence of phosphate. Lanthanum (0.1 mM), a compound known to block transmembrane Ca/sup 2 +/ fluxes, attenuated both actions of CCK-8, but only in the absence of extracellular phosphate. There was a concomitant decrease in amylase secretion induced by 0.1 nM CCK-8 but not by 10 nM CCK-8, without a significant change in cellular ATP levels. The inhibitory actions of lanthanum on CCK-8-stimulated (Ca/sup 2 +/)/sub i/ levels were very rapid and were mimicked only by prolonged incubation of acini in Ca/sup 2 +/-free medium supplemented with EGTA. Omission of phosphate from incubation medium also lowered basal (Ca/sup 2 +/)/sub i/ levels in IM-9 lymphocytes. These findings suggest that extracellular phosphate may modulate resting (Ca/sup 2 +/)/sub i/ levels in pancreatic acini and other cell types and that mobilization of intracellular Ca/sup 2 +/ may partly depend on the availability of a lanthanum-sensitive pool of cell-surface Ca/sup 2 +/ that is not readily removed by EGTA.},
doi = {10.1073/pnas.84.5.1282},
journal = {Proc. Natl. Acad. Sci. U.S.A.; (United States)},
number = ,
volume = 84:5,
place = {United States},
year = {Sun Mar 01 00:00:00 EST 1987},
month = {Sun Mar 01 00:00:00 EST 1987}
}