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Pancreatic acinar cells: effects of lanthanum ions on amylase release and calcium ion fluxes
Author(s) -
Chandler D. E.,
Williams J. A.
Publication year - 1974
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1113/jphysiol.1974.sp010779
Subject(s) - extracellular , calcium , chemistry , amylase , lanthanum , intracellular , isotopes of calcium , biophysics , secretion , medicine , endocrinology , biochemistry , enzyme , biology , inorganic chemistry , organic chemistry
1. The effect of La 3+ on amylase release and Ca 2+ fluxes in mouse pancreatic fragments in vitro was studied. 2. Amylase release was increased by 0·1 m M ‐La 3+ and progressively inhibited by 1·0–10 m M ‐La 3+ . Non‐stimulated and bethanecol stimulated secretion were altered in an identical manner. Inhibition of amylase release was rapid and reversible. 3. Uptake of 45 Ca 2+ was multiphasic with equilibrium with stable Ca 2+ still not complete after 2 hr. La 3+ (10 m M ) limited uptake of 45 Ca 2+ to the extracellular space and slightly decreased total Ca 2+ content. Lower concentrations of La 3+ affected 45 Ca 2+ uptake and total Ca 2+ content in a biphasic manner which paralleled effects on amylase release. 4. La 3+ restricted washout of 45 Ca 2+ to isotope in the extracellular space and abolished the bethanecol‐stimulated increase in 45 Ca 2+ efflux. 5. Uptake of 45 Ca 2+ into intracellular space, as measured by the ‘lanthanum’ method, was not affected by bethanecol. 6. Tissue ultrastructure and Na + and K + content were not affected by La 3+ . 7. It is concluded that an influx of extracellular Ca 2+ is not important for triggering of secretion and that La 3+ may inhibit amylase release by acting on the release process rather than on Ca 2+ influx.