[Effects of neuromedin B and neuromedin C on insulin release from isolated perfused rat pancreas].
Neuromedin B and neuromedin C are novel decapeptides that have recently been isolated from porcine spinal cord and canine intestinal mucosa. We have studied the effects of neuromedin B and neuromedin C on insulin release from the isolated perfused rat pancreas. The effect of neuromedin B was detectable at a concentration of 10mM, and that of neuromedin C was detectable at a concentration of 1nM. Further increase in the concentration of neuromedin B and neuromedin C resulted in dose-dependent increases in insulin secretion. The effectiveness of neuromedin B and neuromedin C as insulinotropic agents depended on the glucose concentration; both were more effective at a higher concentration of glucose. However, insulinotropic effects of these peptides in the presence of 8.3mM glucose were limited to the first 3 min of a 20-min perfusion. These results, coupled with a recent study demonstrating bombesin-like immunoreactivity in nerves in the pancreas, suggest that neuromedin B and neuromedin C exert a direct local action on insulin secretion in the pancreas.
Nakamura
T
T
The Second Department of Internal Medicine, Kobe University School of Medicine.
Otsuki
M
M
Okabayashi
Y
Y
Fujii
M
M
Tani
S
S
Oka
T
T
Fujisawa
T
T
Baba
S
S
D000595:Amino Acid Sequence; D000818:Animals; D001839:Bombesin / Q000008:administration & dosage / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D019886:Gastrin-Releasing Peptide; D005947:Glucose / Q000008:administration & dosage; D066298:In Vitro Techniques; D007328:Insulin / Q000378:metabolism*; D000078790:Insulin Secretion; D007515:Islets of Langerhans / Q000378:metabolism*; D008297:Male; D008969:Molecular Sequence Data; D015287:Neurokinin B / Q000008:administration & dosage / Q000494:pharmacology / Q000031:analogs & derivatives; D010446:Peptide Fragments / Q000008:administration & dosage / Q000494:pharmacology*; D010455:Peptides / Q000494:pharmacology; D010477:Perfusion; D051381:Rats; D011919:Rats, Inbred Strains
D007328:Insulin; D010446:Peptide Fragments; D010455:Peptides; D019886:Gastrin-Releasing Peptide; C040794:neuromedin C; D015287:Neurokinin B; C038393:neuromedin B; D005947:Glucose; D001839:Bombesin