Glucagonostatic and insulinotropic action of glucagonlike peptide I-(7-36)-amide.
We examined the effect of glucagonlike peptides (GLPs), which are cleaved from preproglucagon in the enteroglucagon cells, on rat endocrine pancreas with the isolated perfused system. GLP-I-(7-36)-amide, a truncated form of full-sequence GLP-I-(1-37), showed a potent inhibitory effect on glucagon secretion. This inhibitory effect of GLP-I-(7-36)-amide was demonstrated at concentrations of 0.25, 2.5, and 25 nM in 11.2 and 2.8 mM glucose. In contrast, insulin release was significantly stimulated by GLP-I-(7-36)-amide at its concentration from 0.025 to 25 nM in a high glucose concentration, whereas in a low glucose concentration, the stimulation was seen only at the highest concentration (25 nM). Neither GLP-I-(1-37) nor GLP-II showed any effect on glucagon and insulin release. Although several gastrointestinal hormones have been nominated as incretins, none of them may suppress the glucagon secretion. A truncated form of GLP-I, GLP-I-(7-36)-amide thus seems to be a unique incretin that exerts glucagonostatic action.
Komatsu
R
R
Second Department of Internal Medicine, Osaka University Medical School, Japan.
Matsuyama
T
T
Namba
M
M
Watanabe
N
N
Itoh
H
H
Kono
N
N
Tarui
S
S
D000818:Animals; D005934:Glucagon / Q000378:metabolism*; D052216:Glucagon-Like Peptide 1; D004763:Glucagon-Like Peptides; D005947:Glucose / Q000494:pharmacology; D007328:Insulin / Q000378:metabolism*; D008297:Male; D010179:Pancreas / Q000187:drug effects / Q000378:metabolism*; D010446:Peptide Fragments; D010455:Peptides / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains
D007328:Insulin; D010446:Peptide Fragments; D010455:Peptides; C055453:glucagon-like peptide 1 (7-36)amide; D004763:Glucagon-Like Peptides; C015236:glucagon-like-immunoreactivity; C055968:glucagon-like peptide 1 (1-37); D052216:Glucagon-Like Peptide 1; D005934:Glucagon; D005947:Glucose