TABLE 6.
The magnitude of glucose-stimulated insulin release in human islets is similar to rat islets and β-hydroxybutyrate potentiates glucose-stimulated insulin release
As described under “Experimental Procedures,” islets were incubated with a submaximal stimulatory concentration of glucose (5.6 mm) with or without β-hydroxybutyrate (HB) for 1 h. Stimulation with 16.7 mm glucose, which provides a near maximal insulin release, is shown as a positive control. Results are from up to six experiments with 5–6 replicates for each condition in each experiment with islet preparations from six human donors and are the mean ± S.E. with the number of replicates in parentheses. The mean ± S.E. BMI and age of the human islet donors whose islets were used for these measurements were 28 ± 2.4 kg/m2 and 49.8 ± 4.3 years. Insulin release from up to 6 batches of rat islets with 6–12 replicates for each condition are shown to demonstrate that the magnitude of glucose-induced insulin release from human islets is similar to that from rat islets. Insulin release is expressed in microunits of insulin/μg islet protein/1 h.
| Secretagogue | Insulin release |
|
|---|---|---|
| Human islets | Rat islets | |
| No addition | 16 ± 1 (36) | 12 ± 0.5 (36) |
| Glucose (5.6 mm) | 60 ± 4 (36)a | 57 ± 4 (24)a |
| Glucose (5.6 mm) + HB (5 mm) | 128 ± 8 (36)b | 102 ± 12 (33)b |
| Glucose (5.6 mm) + HB (1 mm) | 91 ± 8 (18)c | |
| HB (5 mm) | 21 ± 3 (12) | 30 ± 2 (37) |
| Glucose (16.7 mm) | 263 ± 23 (33)a | 273 ± 25 (48)a |
a p < 0.001 is versus no addition.
b p < 0.001 is versus glucose (5.6 mm).
c p < 0.002 is versus glucose (5.6 mm).