Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P20366 (substance P)
 21,176 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Luminal application of acid was recently shown to stimulate surface epithelial HCO3(-) transport in stomach and duodenum. Effects of some potential transmitters of this response were therefore studied in amphibian gastric fundic and proximal duodenal mucosa in vitro. Duodenal HCO3- transport, which could be titrated directly, was stimulated by dibutyryl cAMP (DBcAMP, 10(-6) M), the phosphodiesterase inhibitor 3-isobutyl-1-methylxanthine (10(-6) M), noradrenaline (10(-6) M), pancreatic glucagon (10(-8) M), and gastric inhibitory peptide (GIP, 10(-10) M). Stimulation by glucagon, but not by prostaglandin E2 (PGE2, 10(-6) M), required Cl- in the luminal solution and was prevented by furosemide (10(-3) M). This suggests that glucagon may affect HCO3(-)-Cl- exchange at the luminal membrane while transport stimulated by prostaglandins may be electrogenic. Stimulatory effects of glucagon and PGE2 were also additive. Gastric HCO3- transport, studied in tissues after inhibition of H+ secretion by histamine H2-antagonists, clearly differed from duodenum in that noradrenaline and GIP were inhibitory and DBcAMP was without effect. Stimulation of gastric HCO3- transport was observed with glucagon (10(-8) M), natural cholecystokinin (CCK, 10(-8) M), and CCK octapeptide (10(-7) M), CCK preparations had no effect in the duodenum. Although tested over a wide range of concentrations, no effect on either duodenal or gastric HCO3- transport was observed with histamine, pentagastrin, tetragastrin, urogastrone, ACTH, bombesin, motilin, secretin, serotonin, somatostatin, substance P, or vasoactive intestinal peptide.
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PMID:Gastric and duodenal HCO3- transport in vitro: effects of hormones and local transmitters. 697 77

A specific and sensitive radioimmunoassay of human vasoactive intestinal polypeptide using synthetic VIP as standard preparation and antiserum to synthetic VIP R 502 (Yanaihara et al. 15) is described. No crossreactions with a number of other gastrointestinal hormones such as glucagon, secretin, GIP, HPP or substance P was detected. Aprotinin (Trasylol, Bayer) or heparin had no influence on the antigen--antibody reaction. High concentrations of sodium or potassium chloride in plasma, or hyperlipoproteinemia, did not interfere with the antiserum in the described system. Basal plasma concentration of VIP in 18 females (means +/- sem = 24.05 +/- 1.79 VIP/l) and 20 males (means +/- sem = 24.11 +/- 1.91 pmol/l VIP) showed no sex specific variations. During gastroscopy plasma VIP levels were significantly higher than basal values, showing a peak secretion when the gastric antrum was inspected. During the entire colonoscopic examination, VIP levels were significantly higher than basal values. Endoscopic examination may possibly liberate VIP from the VIP containing cells which can be found throughout the gastrointestinal tract.
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PMID:Radioimmunoassay for vasoactive intestinal polypeptide (VIP) in plasma before and during endoscopic examinations. 712 38

Histological, immunocytochemical and immunofluorescence methods were employed to study the intestine and endocrine pancreas of the elephant. The histological findings were in line with those in monogastric mammals. In the mucosa of intestine, endocrine cells were immunoreactive to somatostatin, gastrin, CCK, GIP, secretin, motilin, glucagon and NPY. Nerve cells immunoreactive to somatostatin, substance P, VIP, PHI, NPY, bombesin and CGRP were detected. No immunoreactivity to neurotensin was observed, islets of the pancreas had insulin cells in their cores and glucagon and somatostatin cells in their mantles. The antisera employed failed to demonstrate PP cells in the pancreas, but NPY-immunoreactive cells were present.
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PMID:The intestine and endocrine pancreas of the African elephant: a histological immunocytochemical and immunofluorescence study. 917 65

Ghrelin is produced by A-like cells (ghrelin cells) in the mucosa of the acid-producing part of the stomach. The mobilization of ghrelin is stimulated by nutritional deficiency and suppressed by nutritional abundance. In an attempt to identify neurotransmitters and regulatory peptides that may contribute to the physiological, nutrient-related regulation of ghrelin secretion, we challenged the ghrelin cells in situ with a wide variety of candidate messengers, including known neurotransmitters (e.g. acetylcholine, catecholamines), candidate neurotransmitters (e.g. neuropeptides), local tissue hormones (e.g. serotonin, histamine, bradykinin, endothelin), circulating gut hormones (e.g. gastrin, CCK, GIP, neurotensin, PYY, secretin) and other circulating hormones/regulatory peptides (e.g. calcitonin, glucagon, insulin, PTH). Microdialysis probes were placed in the submucosa of the acid-producing part of the rat stomach. Three days later, the putative messenger compounds were administered via the microdialysis probe (reverse microdialysis) at a screening dose of 0.1 mmol l(-1) for regulatory peptides and 0.1 and 1 mmol l(-1) for amines and amino acids. The rats were awake during the experiments. The resulting microdialysate ghrelin concentration was monitored continuously for 3 h (radioimmunoassay), thereby revealing stimulators or inhibitors of ghrelin secretion. Dose-response curves were constructed for each candidate messenger that significantly (p<0.05) affected ghrelin mobilization at the screening dose. Peptides that showed a (non-significant) tendency to affect ghrelin release at the screening dose were also given at a dose of 0.3 or 1 mmol l(-1). Adrenaline, noradrenaline, endothelin and secretin stimulated ghrelin release, while somatostatin and GRP inhibited. Whether these agents act directly or indirectly on the ghrelin cells remains to be investigated. All other candidate messengers were without measurable effects, including acetylcholine, serotonin, histamine, GABA, aspartic acid, glutamic acid, glycine, VIP, PACAP, CGRP, substance P, NPY, PYY, PP, gastrin, CCK, GIP, insulin, glucagon, GLP and glucose.
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PMID:Secretion of ghrelin from rat stomach ghrelin cells in response to local microinfusion of candidate messenger compounds: a microdialysis study. 1757 35

Given the scarcity of donors, moderately fatty livers (FLs) are currently being considered as possible grafts for orthotopic liver transplantation (OLT), notwithstanding their poor tolerance to conventional cold preservation. The behaviour of parenchymal and sinusoidal liver cells during transplantation is being studied worldwide. Much less attention has been paid to the biliary tree, although this is considered the Achille's heel even of normal liver transplantation. To evaluate the response of the biliary compartment of FLs to the various phases of OLT reliable markers are necessary. Previously we demonstrated that Alkaline Phosphatase was scarcely active in bile canaliculi of FLs and thus ruled it out as a marker. As an alternative, dipeptidylpeptidase-IV (DPP-IV), was investigated. This ecto-peptidase plays an important role in glucose metabolism, rapidly inactivating insulin secreting hormones (incretins) that are important regulators of glucose metabolism. DPP-IV inhibitors are indeed used to treat Type II diabetes. Neuropeptides regulating bile transport and composition are further important substrates of DPP-IV in the enterohepatic axis. DPP-IV activity was investigated with an azo-coupling method in the liver of fatty Zucker rats (fa/fa), using as controls lean Zucker (fa/+) and normal Wistar rats. Protein expression was studied by immunofluorescence with the monoclonal antibody (clone 5E8). In Wistar rat liver, DPP-IV activity and expression were high in the whole biliary tree, and moderate in sinusoid endothelial cells, in agreement with the literature. Main substrates of DPP-IV in hepatocytes and cholangiocytes could be incretins GLP-1 and GIP, and neuropeptides such as vasoactive intestinal peptide (VIP) and substance P, suggesting that these substances are inactivated or modified through the biliary route. In lean Zucker rat liver the enzyme reaction and protein expression patterns were similar to those of Wistar rat. In obese rat liver the patterns of DPP-IV activity and expression in hepatocytes reflected the morphological alterations induced by steatosis as lipid-rich hepatocytes had scarce activity, located either in deformed bile canaliculi or in the sinusoidal and lateral domains of the plasma membrane. These findings suggest that bile canaliculi in steatotic cells have an impaired capacity to inactivate incretins and neuropeptides. Incretin and/or neuropeptide deregulation is indeed thought to play important roles in obesity and insulin-resistance. No alteration in enzyme activity and expression was found in the upper segments of the biliary tree of obese respect to lean Zucker and Wistar rats. In conclusion, this research demonstrates that DPP-IV is a promising in situ marker of biliary functionality not only of normal but also of fatty rats. The approach, initially devised to investigate the behaviour of the liver during the various phases of transplantation, appears to have a much higher potentiality as it could be further exploited to investigate any pathological or stressful conditions involving the biliary tract (i.e., metabolic syndrome and cholestasis) and the response of the biliary tract to therapy and/or to surgery.
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PMID:Dipeptidylpeptidase--IV, a key enzyme for the degradation of incretins and neuropeptides: activity and expression in the liver of lean and obese rats. 2336 Dec 37


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