Abstract
Pancreatic islets were isolated from noninbred ob/ob mice and used for evaluating how removal of extracellular Na+ affects 45Ca fluxes in the insulin-producing β cells. Isoosmotic replacement of Na+ with Li+ was less efficient in stimulating the incorporation of intracellular (La3+ nondisplaceable) 45Ca than substitution with choline+ or sucrose. Ample support for the significance of Na+-Ca2+ exchange for the net efflux of Ca2+ was obtained with the observation that Na+ deprivation markedly inhibited the 45Ca washout in a Ca2+-deficient medium. The inhibitory action of Na+ deficiency exceeded that obtained with 20 mM glucose. The 45Ca incorporated after removal of Na+ differed from that taken in response to glucose in not being exchanged with the Ca2+ entering the β cells during glucose stimulation and in appearing also in the postmicrosomal supernatant obtained by differential centrifugation.
Original language | English (US) |
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Pages (from-to) | 143-152 |
Number of pages | 10 |
Journal | Biochemical medicine |
Volume | 24 |
Issue number | 2 |
DOIs | |
State | Published - 1980 |
ASJC Scopus subject areas
- Biochemistry