TABLE 1

Glucagon and GLP-1 potentiation of 20 mmol/l glucose-induced insulin release from the isolated perfused rat pancreas: effect of the receptor antagonists [des-His1,des-Phe6,Glu9]glucagon-NH2 and exendin-(9-39)-NH2

ConditionReleased insulin (AUC) % of stimulation 1 (min 11–20)
Stimulation 2 (min 36–45)Stimulation 3 (min 61–70)
Control146 ± 16 (4)185 ± 14 (4)
Glucagon (1 nmol/l)300 ± 46 (12)427 ± 65 (4)
Glucagon (1 nmol/l) + [des-His1,des-Phe6,Glu9]Glucagon-NH2 (10 μmol/l)NT230 ± 21 (4)*
Glucagon (1 nmol/l) + exendin-(9-39)-NH2 (1 μmol/l)NT389 ± 61 (4) NS
GLP-1 (1 nmol/l)500 ± 66 (8)742 ± 94 (4)
GLP-1 (1 nmol/l) + exendin-(9-39)-NH2 (1 μmol/l)NT242 ± 44 (4)
  • Data represent the means ± SD of insulin released (AUC after glucose stimulation 2 [min 36–45] or 3 [min 61–70] and expressed as % of AUC after glucose stimulation 1 [min 11–20]) from (n) individual pancreata. Statistical significance of difference between absence or presence of antagonists versus control (stimulation 2), glucagon, or GLP-1 (stimulation 3) was calculated via the two-tailed Student’s t test.

  • *

    * P < 0.02;

  • P < 0.001. NS, not significant;

  • NT, not tested.