| Abstract: | Intracellular calcium concentration (Ca]i) and pepsinogen secretion from dispersed chief cells from guinea pig stomach were determined before and after stimulation with calcium ionophores. Ca]i was measured using the fluorescent probe quin2. Basal Ca]i was 105 +/- 4 nM. Pepsinogen secretion was measured with a new assay using 125I-albumin substrate. This assay is 1000-fold more sensitive than the widely-used spectrophotometric assay, technically easy to perform, rapid, and relatively inexpensive. The kinetics and stoichiometry of ionophore-induced changes in Ca]i and pepsinogen secretion were similar. These data support a role for calcium as a cellular mediator of pepsinogen secretion. |
