[Secretion of insulin and pancreatic polypeptide from the isolated perfused ventral and dorsal portions of the rat pancreas].
The stimulation of the secretion of insulin and pancreatic polypeptide (PP) by carbachol, three different neuropeptides (gastrin-releasing peptide (GRP), vasoactive intestinal polypeptide (VIP) and neuromedin C (NC)), and glucose was investigated using the isolated perfused ventral part of the rat pancreas, with or without atropine. We used a specific radioimmunoassay for the secretion of rat PP. In addition, we studied the secretion of insulin and PP from the dorsal part of the rat pancreas in response to GRP and carbachol. The secretion of insulin and PP in response to carbachol and GRP were dose-dependent in range of 10(-9) M to 10(-6) M. The responses of insulin and PP to carbachol (10(-7) M) were biphasic, and were abolished by atropine (10(-5) M). Those in response to GRP (10(-7) M) were transient, monophasic and not inhibited by atropine (10(-5) M). VIP (10(-7) M) stimulated PP slightly and insulin obviously. Such secretion was not influenced by atropine (10(-5) M). Neuromedin C showed a bioactivity similar to that of GRP with respect to the releases of insulin and PP. Glucose stimulated a biphasic response of insulin, but no response of PP. The relative secretion of PP from the dorsal vs. the ventral portions of the rat pancreas following stimulation by carbachol and GRP (10(-7) M) was 19% and 22%, respectively, while that of insulin was 289% and 382%, respectively. These data show that peptidergic nerves may play a role in the secretion of PP as with that of insulin.(ABSTRACT TRUNCATED AT 250 WORDS)
Miyazaki
K
K
Third Department of Internal Medicine, Faculty of Medicine, Kyushu University, Fukuoka.
D000818:Animals; D001285:Atropine / Q000494:pharmacology; D002217:Carbachol / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D005947:Glucose / Q000494:pharmacology; D066298:In Vitro Techniques; D007328:Insulin / Q000378:metabolism*; D000078790:Insulin Secretion; D008297:Male; D009479:Neuropeptides / Q000494:pharmacology; D010179:Pancreas / Q000166:cytology / Q000378:metabolism*; D010191:Pancreatic Polypeptide / Q000378:metabolism*; D010477:Perfusion; D011863:Radioimmunoassay; D051381:Rats; D011919:Rats, Inbred Strains
D007328:Insulin; D009479:Neuropeptides; D010191:Pancreatic Polypeptide; D001285:Atropine; D002217:Carbachol; D005947:Glucose