Table 1.

Results of the study comparing the rate of Ca²⁺ uptake and release induced by 1 mm ATP and 0.5 μm InsP₃, respectively, in single permeabilized pancreatic acinar cells

Medium pH	Rate of Ca2+ uptake (t1/2) (s)	Initial rate of Ca2+ release (ratio units min−1)
6.7	246 ± 92 (7)	0.28 ± 0.08 (8)*
7.1	403 ± 167 (6)	1.55 ± 0.56 (6)
7.6	575 ± 127 (9)	2.93 ± 1.08 (6)

Assessments of uptake and release rates were carried out at different medium pHs - 6.7, 7.1 (control) and 7.6. The rate of Ca²⁺ uptake was analysed by fitting a mono-exponential time course by non-linear regression to the data. The rate of Ca²⁺ release was not well fitted by a mono-exponential time course and is therefore given as the initial rate of change of the 350:380 ratio/Δtime (minutes).

^*Significantly different from rate at pH 7.1 and 7.6. Values of n given in parentheses.