Figure 1.

A23187 and ATP-induced release of Asc from different cells. (a) Freshly isolated PCEC. Cells were isolated and incubated with DHAA as described in the Methods. For each tube, Asc released in 5 min and that remaining in the cells was determined by HPLC. Percent release was computed as 100 × Asc released/(Asc released+Asc remaining). The values are mean±s.e.m. from data pooled from experiments on five different days from a total of 32, 20 and 17 tubes for control, 100 μM ATP and 10 μM A23187, respectively. Both agents caused a significant (P<0.05) increase in the release. (b) Comparison of ¹⁴C release from cultured PCEC and PCSMC. PCEC and PCSMC were preincubated with ¹⁴C-Asc and used for release in paired experiments. Mean value of total Asc content was 12.9 nmol mg protein⁻¹ in PCEC and 20.9 nmol mg protein⁻¹ in PCSMC. Values are mean±s.e.m. of six replicates. Test–Control values differed significantly from zero (P<0.05) for PCEC but not for PCSMC from the no additive control. The paired experiment was replicated three times and the effect on the two cell types was also examined several times in non-paired experiments.