Glucagon-like peptide-1(7-36)amide enhances insulin-stimulated glucose uptake and decreases intracellular cAMP content in isolated rat adipocytes.
We investigated the effect of GLPs on glucose uptake in isolated rat adipocytes. GLP-1(7-36)amide significantly enhanced glucose uptake in the presence of 1 nM insulin. GLP-1(7-36)amide at 15 nM increased glucose uptake maximally by 56.4% as compared with 1 nM insulin alone (P < 0.01). In contrast, with less than 1 nM insulin or without insulin GLP-1(7-36)amide showed no effect on glucose uptake. Full-sequence GLP-1(1-37) at 15 nM in the presence of 1 nM insulin increased glucose uptake by 24.6% as compared with 1 nM insulin alone (P < 0.05). GLP-2 showed no effect on glucose uptake. Further, we examined the effect of GLP-1(7-36)amide on cAMP content in isolated rat adipocytes. Insulin at 1 nM caused a significant decrease of cAMP content. The combination of 15 nM GLP-1(7-36)amide and 1 nM insulin caused a further reduction of cAMP content. These data indicate that GLP-1(7-36)amide possesses augmentative effects on insulin action in isolated rat adipocytes. Furthermore, it is suggested that the stimulatory effect of GLP-1(7-36)amide occurs through the reduction of intracellular cAMP content.
Miki
H
H
Second Department of Internal Medicine, Osaka University Medical School, Japan.
Namba
M
M
Nishimura
T
T
Mineo
I
I
Matsumura
T
T
Miyagawa
J
J
Nakajima
H
H
Kuwajima
M
M
Hanafusa
T
T
Matsuzawa
Y
Y
D015056:1-Methyl-3-isobutylxanthine / Q000494:pharmacology; D017667:Adipocytes / Q000187:drug effects / Q000378:metabolism*; D000818:Animals; D005576:Colforsin / Q000494:pharmacology; D000242:Cyclic AMP / Q000378:metabolism*; D005934:Glucagon; D052216:Glucagon-Like Peptide 1; D053767:Glucagon-Like Peptide 2; D004763:Glucagon-Like Peptides; D005947:Glucose / Q000378:metabolism*; D007328:Insulin / Q000494:pharmacology*; D008297:Male; D010446:Peptide Fragments / Q000494:pharmacology*; D010455:Peptides / Q000494:pharmacology; D010726:Phosphodiesterase Inhibitors / Q000494:pharmacology; D051381:Rats
D053767:Glucagon-Like Peptide 2; D007328:Insulin; D010446:Peptide Fragments; D010455:Peptides; D010726:Phosphodiesterase Inhibitors; C055453:glucagon-like peptide 1 (7-36)amide; D005576:Colforsin; D004763:Glucagon-Like Peptides; D052216:Glucagon-Like Peptide 1; D005934:Glucagon; D000242:Cyclic AMP; D005947:Glucose; D015056:1-Methyl-3-isobutylxanthine