Table 1.

Insulin secretion from MIN6 monolayer cells, pseudoislets and human islets in the presence of different secretagogues

Secretagogue	Insulin secretion [fmol (μg protein)−1]
	Monolayer cells	Pseudoislets	Human islets
Glu 2 mmol/l	5.1 ± 0.8	6.4 ± 0.1	8.4 ± 0.6
Glu 20 mmol/l, first phase	7.5 ± 0.8*†	36.1 ± 0.7*	54.3 ± 8.6*
Glu 20 mmol/l, second phase	6.9 ± 0.8*†	45.1 ± 12.3*	43.6 ± 7.3*
Glu 2 mmol/l	6.8 ± 0.2	6.3 ± 0.8	11.5 ± 3.2
Pyr first phase	8.4 ± 0.2	11.3 ± 3.7*	14.7 ± 1.3†
Pyr second phase	8.0 ± 0.9†	15.7 ± 1.7*	10.7 ± 2.9
Glu 2 mmol/l	7.1 ± 0.4	8.7 ± 1.6	16.7 ± 6.2
KIC first phase	7.9 ± 0.3†	21.5 ± 2.5*	42.9 ± 10.2*†
KIC second phase	11.9 ± 0.6*	15.3 ± 2.3*	39.3 ± 14.5*†
Glu 2 mmol/l	7.9 ± 0.2	7.1 ± 0.16	14.4 ± 4.6
KIC + Gln first phase	13.6 ± 0.5*	17.2 ± 2.3*	59.0 ± 3.5*†
KIC + Gln second phase	11.9 ± 0.5*†	20.5 ± 2.5*	43.2 ± 13.8*†
Glu 2 mmol/l	4.4 ± 0.1	8.5 ± 0.61	13.0 ± 4.5
KCl first phase	10.1 ± 0.8*	15.2 ± 0.3*	37.8 ± 8.9*†
KCl second phase	12.1 ± 0.3*	7.2 ± 2.7	6.1 ± 0.6*

Results are means ± SEM of between five and eight separate experiments, which were obtained by calculating the area under the curve from each group of the experiments in Fig. 3

Cells and islets were perifused in the presence of 2 or 20 mmol/l glucose (Glu), 2 mmol/l pyruvate (Pyr), 20 mmol/l KIC, and 10 mmol/l KIC plus 10 mmol/l glutamine (Gln) or 30 mmol/l KCl. Secreted insulin was measured for 10 min at 2 mmol/l glucose and in the initial (first phase) and subsequent (second phase) 10 min after the introduction of secretagogues

*p < 0.05 compared with 2 mmol/l glucose; ^† p < 0.05 compared with pseudoislets