The Experts below are selected from a list of 93 Experts worldwide ranked by ideXlab platform
Kyoko Hotta - One of the best experts on this subject based on the ideXlab platform.
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Influence of L-365,260, a CCK-B/Gastrin Receptor Antagonist, on Tetragastrin- Stimulated Mucin Metabolism in Rat Gastric Mucosa
Pharmacology, 1999Co-Authors: Yuichi Komuro, Kazuhiko Ishihara, Katsunori Saigenji, Takafumi Ichikawa, Kyoko HottaAbstract:The effect of L-365,260, a CCK-B/gastrin receptor antagonist, on gastric mucus metabolism induced by Tetragastrin was investigated in rats. In vivo application of L-365,260 at a dose of 3 mg/kg p.o. s
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Age-related stimulation by Tetragastrin of gastric mucin biosynthesis in rat.
European journal of pharmacology, 1999Co-Authors: Takafumi Ichikawa, Kazuhiko Ishihara, Tatsumi Kusakabe, Tadashi Kawakami, Kyoko HottaAbstract:The effects of Tetragastrin on gastric mucin biosynthesis in middle-aged rats were compared with those in young rats. The incorporation of [3H]glucosamine and [35S]sulfate into mucin was stimulated by Tetragastrin in cultured corpus mucosa from 7-week-old rats. In contrast, Tetragastrin could not enhance mucin biosynthesis in stomachs from 52-week-old rats. The isosorbide dinitrate-induced stimulation of corpus mucin biosynthesis observed in middle-aged rats was essentially the same as that seen in young rats. Nitric oxide (NO) synthase activity of the corpus was significantly reduced in the middle-aged rats compared to the young rats. NO synthase-immunoreactivity was observed at surface mucous cells in the corpus mucosa of young, but not of middle-aged, rats. These results suggest that aging decreases the effect of gastrin on gastric mucin biosynthesis through the age-related loss of NO synthase function in the surface mucous cell layer of rat stomach.
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Distinct effects of Tetragastrin in rat gastroduodenal mucosa on mucin content and mucosal protective action against histamine-induced injury
Digestive diseases and sciences, 1998Co-Authors: Yuichi Komuro, Kazuhiko Ishihara, Yoji Kojima, Katsunori Saigenji, Kyoko HottaAbstract:We examined the effects of Tetragastrin on mucin (mucus glycoprotein) content and mucosal damage in the rat stomach and duodenum. Following an injection of Tetragastrin (12, 120, or 400 microg/kg subcutaneously), no macroscopic damage was found to the gastric mucosa but an increase in corpus mucin content was noted, whereas mucosal lesions appeared and the mucin content decreased in the duodenum in a dose-related manner. In the groups with histamine (0.8, 8, or 80 mg/kg intraperitoneally) administration, the extent of mucosal damage and the decrease in mucin content were dose-related in both these regions. For assessment of the effect of Tetragastrin on the protective action in gastroduodenal mucosa, changes in mucin content and mucosal damage with histamine (80 mg/kg) -induced injury were examined. Coadministration of Tetragastrin prevented the gastric mucosal damage and inhibited the decrease in corpus mucin content. In the duodenum, Tetragastrin aggravated the histamine-induced mucosal damage and did not inhibit the reduction of the mucin content. From the present results, the increase in gastric mucins induced by Tetragastrin might be related to the protective effect of gastric mucosa against injury. Tetragastrin did not protect the duodenal mucosa, and histamine-induced injury occurring in this region would be aggravated by the increase in HCl secretion and the decrease in mucin content induced by Tetragastrin.
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Effects of Tetragastrin on mucus glycoprotein in rat gastric mucosal protection
Gastroenterologia Japonica, 1992Co-Authors: Yuichi Komuro, Kazuhiko Ishihara, Katsunori Saigenji, Susumu Ohara, Kyoko HottaAbstract:The effects of Tetragastrin on mucus glycoprotein (mucin) metabolism and mucosal protection in rat gastric mucosa were investigated. Rats were administered with various doses of Tetragastrin (12, 120, or 400 [μg/kg body weight; s.c), followed by 50% ethanol-induced gastric injury. Tetragastrin caused a significant increase in mucin content in the corpus mucosa and prevented 50% ethanol-induced gastric mucosal damage in a dose-dependent manner. For assessment of the effects of Tetragastrin on the metabolism of gastric mucin in detail, changes in mucin distribution in the three different layers of rat gastric mucosa were examined one hour after single administration of Tetragastrin. A significant increase in the mucin content was noted in the mucus gel and surface mucosal layer. Mucin content in the deep mucosa corresponding mainly to the mucus neck cell mucin underwent virtually no change by this treatment. An increase in mucin in the mucus gel and surface mucosa would thus appear due to the administration of Tetragastrin and may possibly be related to the protective action of the gastric mucosa against injury. The data demonstrate a possibility that gastrin may have potential for enhancing gastric mucosal protection associated with mucus secretion and/or mucus synthesis on the surface mucosa of rat gastric mucosa.
Takashi Kanematsu - One of the best experts on this subject based on the ideXlab platform.
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Bile acid inhibits Tetragastrin-stimulated gastric secretion after Roux-en-Y biliary diversion in dogs
Journal of Hepato-Biliary-Pancreatic Surgery, 1995Co-Authors: Hideaki Shimogama, Toshifumi Eto, Takashi KanematsuAbstract:The present study was carried out to investigate the effect of several bile acids on Tetragastrin-stimulated gastric secretion in dogs in which diversion of the biliary system was performed. Cholecystojejunostomy of the Roux-en-Y type was performed, along with the creation of a Heidenhain pouch (HP) and an external duodenal fistula. Gastric juice was collected from the HP and a mixture of bile acids and corn oil was administered through the duodenal fistula. Ursodeoxycholic acid (UDCA) and chenodeoxycholic acid (CDCA) exerted an inhibitory effect on gastric hypersecretion. Conjugated UDCA and several bile acids with different hydroxyl groups were also examined, and these bile acids also showed evidence of an inhibitory effect on the secretion of gastric juice, although there were no significant differences between them. Thus, it appears that all bile acids inhibit Tetragastrin-stimulated gastric hypersecretion. This finding suggests that peptic ulcer disease can be prevented by the administration of bile acids to patients who undergo biliary diversion and are at a high risk for this postoperative complication.
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Bile acid inhibits Tetragastrin‐stimulated gastric secretion after Roux‐en‐Y biliary diversion in dogs
Journal of Hepato-Biliary-Pancreatic Surgery, 1995Co-Authors: Hideaki Shimogama, Toshifumi Eto, Takashi KanematsuAbstract:The present study was carried out to investigate the effect of several bile acids on Tetragastrin-stimulated gastric secretion in dogs in which diversion of the biliary system was performed. Cholecystojejunostomy of the Roux-en-Y type was performed, along with the creation of a Heidenhain pouch (HP) and an external duodenal fistula. Gastric juice was collected from the HP and a mixture of bile acids and corn oil was administered through the duodenal fistula. Ursodeoxycholic acid (UDCA) and chenodeoxycholic acid (CDCA) exerted an inhibitory effect on gastric hypersecretion. Conjugated UDCA and several bile acids with different hydroxyl groups were also examined, and these bile acids also showed evidence of an inhibitory effect on the secretion of gastric juice, although there were no significant differences between them. Thus, it appears that all bile acids inhibit Tetragastrin-stimulated gastric hypersecretion. This finding suggests that peptic ulcer disease can be prevented by the administration of bile acids to patients who undergo biliary diversion and are at a high risk for this postoperative complication.
Shozo Muranishi - One of the best experts on this subject based on the ideXlab platform.
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Permeability characteristics of Tetragastrins across intestinal membranes using the Caco-2 monolayer system: comparison between acylation and application of protease inhibitors.
Pharmaceutical research, 1998Co-Authors: Takuya Fujita, Shozo Muranishi, Iichiro Kawahara, Ying-shu Quan, Koji Hattori, Kayo Takenaka, Akira YamamotoAbstract:Purpose. Three types of acyl Tetragastrin (TG), acetyl-TG (C2-TG), butyryl-TG (C4-TG) and caproyl-TG (C6-TG) were synthesized and their in vitro intestinal permeability characteristics were examined using Caco-2 monolayers.
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Improvement of transdermal delivery of Tetragastrin by lipophilic modification with fatty acids.
The Journal of pharmacy and pharmacology, 1995Co-Authors: Kazunari Setoh, Masahiro Murakami, Naoko Araki, Takuya Fujita, Akira Yamamoto, Shozo MuranishiAbstract:The in-vitro permeability of chemically modified Tetragastrin with fatty acids through the rat skin was studied. The permeability of these compounds through intact skin and stripped skin of rat was determined with a Franz-type diffusion cell. The permeation of Tetragastrin across the intact skin was improved by chemical modification with acetic acid and butyric acid. However, Tetragastrin and caproyl-Tetragastrin did not permeate across the intact skin up to the end of experiment. The permeation of Tetragastrin across the stripped skin was improved by chemical modification, the skin flux of these acyl derivatives being in the order: acetyl > butyroyl > caproyl. The stability of Tetragastrin in skin homogenate was also significantly improved by chemical modification with fatty acids. These results suggest that chemical modification of Tetragastrin with fatty acids increases its lipophilicity, which makes it permeable across the stratum corneum. Moreover, the chemical modification reduced the degradation of Tetragastrin in the viable skin, resulting an increase in permeation of Tetragastrin across the skin.
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Development of New Lipophilic Derivatives of Tetragastrin: Physicochemical Characteristics and Intestinal Absorption of Acyl-Tetragastrin Derivatives in Rats
Pharmaceutical Research, 1993Co-Authors: Takehiro Tenma, Masahiro Murakami, Takuya Fujita, Akira Yamamoto, Etsuo Yodoya, Shigeru Tashima, Shozo MuranishiAbstract:In order to improve the intestinal absorption of Tetragastrin (TG), we synthesized lipophilic derivatives of TG by acylation of its N-terminal amino group with acetic acid, caproic acid, and lauric acid. The purified TG derivatives, acetyl-Tetragastrin (Ac-TG), caproyl-Tetragastrin (Cap-TG), and lauroyl-Tetragastrin (Lau-TG), were confirmed to be more lipophilic than the parent TG by high-performance liquid chromatography (HPLC). The pharmacological activities and the intestinal absorption of TG and its derivatives were examined by measuring gastric acid secretion. Stimulation of gastric acid secretion by these derivatives after intravenous administration was stronger than with native TG. When the acetyl- and caproyl-derivatives were administered into the large intestinal loops, a marked increase in gastric acid secretion was observed in comparison with TG, while no significant effect occurred following administration of the TG derivatives into the small intestines. These results indicated that chemical modification of TG with fatty acids improves the absorption of TG from the large intestines.
Hideaki Shimogama - One of the best experts on this subject based on the ideXlab platform.
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Bile acid inhibits Tetragastrin-stimulated gastric secretion after Roux-en-Y biliary diversion in dogs
Journal of Hepato-Biliary-Pancreatic Surgery, 1995Co-Authors: Hideaki Shimogama, Toshifumi Eto, Takashi KanematsuAbstract:The present study was carried out to investigate the effect of several bile acids on Tetragastrin-stimulated gastric secretion in dogs in which diversion of the biliary system was performed. Cholecystojejunostomy of the Roux-en-Y type was performed, along with the creation of a Heidenhain pouch (HP) and an external duodenal fistula. Gastric juice was collected from the HP and a mixture of bile acids and corn oil was administered through the duodenal fistula. Ursodeoxycholic acid (UDCA) and chenodeoxycholic acid (CDCA) exerted an inhibitory effect on gastric hypersecretion. Conjugated UDCA and several bile acids with different hydroxyl groups were also examined, and these bile acids also showed evidence of an inhibitory effect on the secretion of gastric juice, although there were no significant differences between them. Thus, it appears that all bile acids inhibit Tetragastrin-stimulated gastric hypersecretion. This finding suggests that peptic ulcer disease can be prevented by the administration of bile acids to patients who undergo biliary diversion and are at a high risk for this postoperative complication.
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Bile acid inhibits Tetragastrin‐stimulated gastric secretion after Roux‐en‐Y biliary diversion in dogs
Journal of Hepato-Biliary-Pancreatic Surgery, 1995Co-Authors: Hideaki Shimogama, Toshifumi Eto, Takashi KanematsuAbstract:The present study was carried out to investigate the effect of several bile acids on Tetragastrin-stimulated gastric secretion in dogs in which diversion of the biliary system was performed. Cholecystojejunostomy of the Roux-en-Y type was performed, along with the creation of a Heidenhain pouch (HP) and an external duodenal fistula. Gastric juice was collected from the HP and a mixture of bile acids and corn oil was administered through the duodenal fistula. Ursodeoxycholic acid (UDCA) and chenodeoxycholic acid (CDCA) exerted an inhibitory effect on gastric hypersecretion. Conjugated UDCA and several bile acids with different hydroxyl groups were also examined, and these bile acids also showed evidence of an inhibitory effect on the secretion of gastric juice, although there were no significant differences between them. Thus, it appears that all bile acids inhibit Tetragastrin-stimulated gastric hypersecretion. This finding suggests that peptic ulcer disease can be prevented by the administration of bile acids to patients who undergo biliary diversion and are at a high risk for this postoperative complication.
Haruo Ohnishi - One of the best experts on this subject based on the ideXlab platform.
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gastric antisecretory effect of frg 8813 a new histamine h2 receptor antagonist in rats and dogs
European Journal of Pharmacology, 1993Co-Authors: Masahiro Shibata, Tetsuaki Yamaura, Niro Inaba, Sadayoshi Onodera, Yuriko Chida, Haruo OhnishiAbstract:FRG-8813, a new histamine H2 receptor antagonist, was examined for antisecretory effects and compared with famotidine and cimetidine in rats and dogs. In pylorus-ligated and lumen-perfused rats, FRG-8813 given i.v. reduced basal gastric acid secretion and the acid secretion evoked by histamine, Tetragastrin, bethanechol, and 2-deoxy-D-glucose in a dose-dependent manner. The i.v. antisecretory activity of FRG-8813 was equivalent to or slightly less than that of famotidine and the intraduodenal (i.d.) activity was greater than that of cimetidine. The duration of action of FRG-8813 was substantially longer than that of farmotidine and cimetidine for both i.v. and i.d. routes. The i.v. ED40 values for the histamine- and Tetragastrin-evoked responses and the i.v. ED30 value for the bethanechol-evoked response were 0.15, 0.09 and 0.43 mg2kg, respectively. In Heidenhain pouch dogs, when the three H2 antagonists were given i.v. or orally, the relative antisecretory potency of the compounds was similar to that in rats. The long-lasting antisecretory effect of FRG-8813 was also observed, and the i.v. ED50 values for histamine-, Tetragastrin- and bethanechol-evoked responses were 0.1, 0.24 and 1.0 mg/kg, respectively. Comparison of the parenteral and enteral potencies indicated that FRG-8813 has a lower bioavailability than famotidine and cimetidine in rats and dogs. These data suggest that FRG-8813 has a potent and long-lasting antisecretory effect with a far greater potency than cimetidine and with a slightly lower potency than famotidine.