Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P01350 (gastrin)
 9,683 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Two hundred millilitres of an isotonic solution of CaCl2 (0,118 M) were injected and left 15 min in the stomach of normal subjects (SN1; n = 21), of patients with gastric ulcer (UG; n = 16), patients with duodenal ulcer (UD; n = 40), patients with normochlorhydric gastritis (G1; n = 13) and patients with hypo- or achlorhydric gastritis (G2; n = 7). Gastric acid secretion and gastrinemia were measured during 90 min. After intragastric calcium injection, the acid secretion was increased during 60 min in almost all subjects (87 to 100 p. 100 of subjects in the various groups) whereas gastrin release was increased in the majority (57 to 84 p. 100) of cases. The possible dissociation between the acid and gastrinic responses implies that the calcium-induced acid response is independent of the calcium-induced gastrin release. During control experiments in normal individuals, continuous intragastric perfusion (300 ml/h) of NaCl 0.15 M failed to alter gastric acid secretion or gastrin release, whereas continuous intragastric perfusion of CaCl2 0,118 M enhanced gastric acid secretion and gastrin release. The action of CaCl2 0,118 M is therefore not attributable to gastric distension but directly to calcium itself. The stimulation of acid secretion by intragastric calcium was more conspicuous in patients with gastric or duodenal ulcer than in normal subjects. The release of gastrin was higher in gastritis and duodenal ulcer than in the normal group. It is hypothesized that intragastric calcium increases the cholinergic tone of the parietal cell.
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PMID:[Effects of intragastric calcium on gastric acid secretion and release of gastrin in normal man and in various pathological cases]. 661 72

Chemical synthesis of tyrosine O-sulfated peptides is still a laborious task for peptide chemists because of the intrinsic acid-lability of the sulfate moiety. An efficient cleavage/deprotection procedure without loss of the sulfate is the critical difficulty remaining to be solved for fluoren-9-ylmethoxycarbonyl (Fmoc)-based solid-phase synthesis of sulfated peptides. To overcome the difficulty, TFA-mediated solvolysis rates of a tyrosine O-sulfate [Tyr(SO3H)] residue and two protecting groups, tBu for the hydroxyl group of Ser and 2,2,4,6,7-pentamethyldihydrobenzofuran-5-sulfonyl (Pbf) for the guanidino group of Arg, were examined in detail. The desulfation obeyed first-order kinetics with a large entropy (59.6 J.K-1.mol-1) and enthalpy (110.5 kJ.mol-1) of activation. These values substantiated that the desulfation rate of the rigidly solvated Tyr(SO3H) residue was strongly temperature-dependent. By contrast, the SN1-type deprotections were less temperature-dependent and proceeded smoothly in TFA of a high ionizing power. Based on the large rate difference between the desulfation and the SN1-type deprotections in cold TFA, an efficient deprotection protocol for the sulfated peptides was developed. Our synthetic strategy for Tyr(SO3H)-containing peptides with this effective deprotection protocol is as follows: (i) a sulfated peptide chain is directly constructed on 2-chlorotrityl resin with Fmoc-based solid-phase chemistry using Fmoc-Tyr(SO3Na)-OH as a building block; (ii) the protected peptide-resin is treated with 90% aqueous TFA at 0 degree C for an appropriate period of time for the cleavage and deprotection. Human cholecystokinin (CCK)-12, mini gastrin-II (14 residues), and little gastrin-II (17 residues) were synthesized with this method in 26-38% yields without any difficulties. This method was further applied to the stepwise synthesis of human big gastrin-II (34 residues), CCK-33 and -39. Despite the prolonged acid treatment (15-18 h at 0 degree C), the ratios of the desulfated peptides were less than 15%, and the pure sulfated peptides were obtained in around 10% yields.
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PMID:Facile solid-phase synthesis of sulfated tyrosine-containing peptides: total synthesis of human big gastrin-II and cholecystokinin (CCK)-39. 1142 84