Insulin secretion by single β-cells in response to a 1-h incubation to NGF in different extracellular glucose concentrations
| Treatment | Glucose (mmol/l) | Percentage of plaque-forming cells | Plaque area (μmol/l) |
|---|---|---|---|
| Control | 5.6 | 41 ± 2 | 1,280 ± 113 |
| 15.6 | 51 ± 3* | 2,299 ± 119* | |
| NGF | 5.6 | 56 ± 3† | 2,152 ± 160† |
| 15.6 | 66 ± 2*† | 3,189 ± 198*† | |
| Nifedipine | 5.6 | 29 ± 4‡ | 1,078 ± 270 |
| 15.6 | 32 ± 2† | 1,160 ± 191† | |
| NGF + nifedipine | 5.6 | 32 ± 3§ | 1,186 ± 174§ |
| 15.6 | 29 ± 4§ | 1,828 ± 506§ |
Data are mean ± SE unless otherwise indicated.
* Denotes significance level with respect to its own control in 5.6 mmol/l glucose, in both groups (P < 0.01). Significance level of experimental cells with respect to control cells in both glucose concentrations: P < 0.01
† , P < 0.05
‡ Significance level of NGF + nifedipine with respect to NGF-treated cells in both glucose concentrations: P < 0.01
§ ; n = 13 experiments by duplicate for control and NGF, and n = 5 for nifedipine alone or with NGF.