Ghrelin infused into the portal vein inhibits glucose-stimulated insulin secretion in Wistar rats.
Although accumulating evidence has shown crucial roles of ghrelin and insulin in food intake and energy metabolism, the exact relationship between these hormones remains unclear. In this study, we determined the in vivo effect of ghrelin on insulin secretion. We demonstrated that ghrelin inhibited the glucose-stimulated release of insulin when infused into the portal vein of Wistar rats. However, ghrelin infusion into the femoral vein did not induce such an inhibitory effect. Hepatic vagotomy or coinfusion with atropine methyl bromide diminished the inhibitory effect of ghrelin on glucose-stimulated insulin secretion. In conclusion, ghrelin exerts an inhibitory effect on glucose-stimulated insulin secretion via the hepatic portal system and the vagus nerve. The decrease in ghrelin level after a meal is important for the occurrence of the incretin effect in rats.
Cui
Can
C
Department of Neurology, Hematology, Endocrinology, Metabolism and Diabetology, Yamagata University School of Medicine, 2-2-2 Iida-Nishi, Yamagata 990-9585, Japan. cuican_72@yahoo.co.jp
Ohnuma
Hiroshi
H
Daimon
Makoto
M
Susa
Shinji
S
Yamaguchi
Hiroshi
H
Kameda
Wataru
W
Jimbu
Yumi
Y
Oizumi
Toshihide
T
Kato
Takeo
T
D000215:Acylation; D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D054439:Ghrelin / Q000008:administration & dosage*; D005947:Glucose / Q000378:metabolism* / Q000494:pharmacology; D007262:Infusions, Intravenous; D007328:Insulin / Q000097:blood / Q000378:metabolism*; D000078790:Insulin Secretion; D008297:Male; D011169:Portal Vein / Q000502:physiology; D011863:Radioimmunoassay; D051381:Rats; D017208:Rats, Wistar
D001786:Blood Glucose; D054439:Ghrelin; D007328:Insulin; D005947:Glucose