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PubMed1981

Purification and characterization of embryonic chicken pepsinogen, a unique pepsinogen with large molecular weight.

An embryo-specific pepsinogen was isolated from the proventriculi of 15-day-old chicken embryos and purified by means of fractionation with ammonium sulfate, filtration on Sephadex G-100, and chromatography on DEAE-Sepharose CL-6B and hydroxyapatite. The properties of this pepsinogen and pepsin derived from it were compared with those of an adult-specific chicken pepsinogen and its pepsin. Though the optimal pH and alkali-stability were similar in the two pepsinogens, molecular weight, sensitivity to pepstatin, and antigenicity were quite different. Among the properties of this embryo-specific pepsinogen, the large molecular weight (56,000 for pepsinogen and 53,000 for pepsin) is especially noteworthy, since the molecular weights of the known pepsinogens of mammals and birds fall into the range of 35,000-48,000.

Animals↗
PubMed1994

Helicobacter pylori infection and serum pepsinogen A, pepsinogen C, and gastrin in gastritis and peptic ulcer: significance of inflammation and effect of bacterial eradication.

OBJECTIVES: To study the relationship between Helicobacter pylori infection, gastric inflammatory scores, and fasting gastrin and pepsinogen A and C concentrations, and to evaluate the effect of treatment on these parameters. METHODS: Gastrin and pepsinogen A and C concentrations were measured in 36 patients with gastritis, 10 gastric ulcer patients, 12 duodenal ulcer patients, and in 15 subjects with normal gastric mucosa, by standard radioimmunoassay techniques. Fifteen patients with H. pylori infection underwent triple therapy (bismuth subsalicylate, amoxicillin, metronidazole) and were reassessed 1 month later. RESULTS: Fasting gastrin and pepsinogen A and C concentrations were significantly higher in H. pylori-positive gastritis and peptic ulcer patients than in subjects with normal mucosa and in patients with H. pylori-negative gastritis. There was a significant correlation between inflammatory scores and serum gastrin (r = 0.45, p < 0.0001), and pepsinogen A (r = 0.33, p < 0.006) and pepsinogen C (r = 0.55, p < 0.0001) concentrations. Neither sex nor age affected basal gastrin and pepsinogen concentrations. Eradication of H. pylori infection was successful in 12 patients and resulted in a significant fall in serum gastrin and in pepsinogen A and C concentrations, and in a concomitant improvement of the inflammatory scores. Serum peptide levels and gastritis scores were unchanged in those patients in whom H. pylori infection persisted. CONCLUSIONS: These findings suggest that hypergastrinemia and hyperpepsinogenemia are secondary to H. pylori infection and are related to mucosal inflammation.

Amoxicillin↗
PubMed1997

Lansoprazole elevates the ratio of serum pepsinogen I v.s. pepsinogen II.

In order to investigate the mechanism by which proton pump inhibitor increases serum pepsinogen levels, we evaluated the effects of ulcer location and IgG antibody against Helicobacter pylori on lansoprazole-induced elevations. Patients with endoscopically proven peptic ulcer received lansoprazole 30 mg/day for 6 or 8 weeks; pepsinogen I and II levels, along with antibody to H. pylori, were measured in fasting blood samples. We found that whether or not antibody to H. pylori was present, pepsinogen I and II levels and the I/II ratio rose significantly in lansoprazole-treated patients. Patients with stomach-body ulcers showed smaller increases in both pepsinogens than did those with ulcers in the gastric angle/antrum or in the duodenum. In conclusion, lansoprazole increases serum levels of both pepsinogens I and II, although a larger increase in pepsinogen I elevates the pepsinogen I/II ratio. The relatively small increases seen in patients with stomach-body ulcers suggest atrophic changes in the gastric mucosa in patients with stomach-body ulcer.

2-Pyridinylmethylsulfinylbenzimidazoles↗
PubMed1988

Analysis of the activation of pepsinogen in the presence of protein substrates and estimation of the intrinsic proteolytic activity of pepsinogen.

Monkey pepsinogen A, monkey progastricsin, and porcine pepsinogen A were activated in the presence of two different protein substrates, namely, reduced and carboxymethylated lysozyme and hemoglobin. In each case, an extensive delay in activation was observed. The intermolecular activation reaction required for the generation of pepsin or gastricsin was strongly inhibited and this inhibition was essentially responsible for the delay. However, the intramolecular reaction required for the generation of the intermediate forms of the proenzymes was scarcely affected. The delay was longer at pH 3.0 than at pH 2.0. Irrespective of the delay in activation of pepsinogen, the digestion of substrates proceeded rapidly, evidence of the significant proteolytic activity of pepsinogen itself. Kinetic experiments demonstrated that pepsinogen changed from an enzymatically inactive species to an active species before the release of the activation segment. The proteolytic activity of the active pepsinogen was highest at pH 2.0, at 37 degrees C and the activity under these conditions was comparable to that of pepsin.

Amino Acid Sequence↗
PubMed1980

Monkey pepsinogens and pepsins. IV. The amino acid sequence of the activation peptide segment of Japanese monkey pepsinogen.

The complete amino acid sequence of the activation peptide segment of the major component of Japanese monkey pepsinogens was determined. The pepsinogen was converted to pepsin by incubation at pH 2.0 and 14 degrees C for 17 min. The activation peptides were separated from the resulting pepsin and purified by chromatography on columns of sulfopropyl (SP)-Sephadex. One 25-residue peptide and two 22-residue peptides were isolated and their amino acid sequences were determined. The results showed that the former peptide was derived from the amino-terminal half (residues no. 1 to 25) and the latter peptides from the carboxyl-terminal half (residues no. 26 to 47) of the activation segment. The latter two peptides were identical except for a single amino acid replacement. The complete amino acid sequence of the whole activation peptide segment was thus deduced as follows: Ile1-Ile-Tyr-Lys-Val-Pro-Leu-Val-Arg-Lys10-Lys-Ser-Leu-Arg-Arg-Asn-Leu-Ser-Glu- His20-Gly-Leu-Leu-Lys-Asp-Phe-Leu-Lys-Lys-His30-Asn-Leu-Asn-Pro-Ala-Ser-Lys-Tyr -Phe-Pro40-LysGln-Ala-Glu-Ala-Pro-Thr-Leu47. The whole chain was composed of 47 residues, and cleaved into two polypeptides by the cleavage of Asp25-Phe26 bond during activation. Two amino acids were detected at residue-41, i.e., glutamine and lysine, indicating the presence of two closely related pepsinogens in the sample used. The total number of residues (47) of the whole activation peptide segment is 3 and 2 residues larger than those of porcine pepsinogen and bovine pepsinogen, respectively. The differences are 15 and 22 residues as compared with porcine pepsinogen and bovine pepsignogen, respectively.

Amino Acid Sequence↗
PubMed1985

Monkey pepsinogens and pepsins. VII. Analysis of the activation process and determination of the NH2-terminal 60-residue sequence of Japanese monkey progastricsin, and molecular evolution of pepsinogens.

Japanese monkey progastricsin was shown to be activated to gastricsin exclusively by a two-step process through an intermediate form. The occurrence of this process was substantiated by the isolation of the intermediate form and released peptides. By NH2-terminal sequence analyses of these protein and peptide species, the amino acid sequence of the 43-residue activation segment (propart) was determined to be as follows: (Formula: see text) The NH2-terminal 26-residue peptide was released first, resulting in generation of the intermediate form. The subsequent release of peptides, residues Nos. 27-40 and 27-43, generated two gastricsins as the final products. This two-step process of activation of Japanese monkey progastricsin is in striking contrast to the one-step activation process occurring exclusively for pepsinogen A of the same monkey species. The course of molecular evolution of pepsinogens including progastricsins was deduced from the amino acid sequences of their activation segments by constructing phylogenic trees. The trees divided pepsinogens into 3 clusters, i.e., pepsinogens A, progastricsins and prochymosin, showing that these three groups diverged from one another very early on in the course of the evolution of pepsinogens.

Amino Acid Sequence↗
PubMed1981

Induction of changes in the pepsinogen content and the pepsinogen isoenzyme pattern of the pyloric mucosa of the rat stomach by short-term administration of stomach carcinogens.

Changes in pepsinogen isoenzyme patterns were examined in the pyloric mucosae of the stomachs of noninbred male Wistar rats after short-term administration of gastric carcinogens. N-Methyl-N-nitro-N-nitrosoquanidine, N-ethyl-N1-nitro-N-nitrosoguanidine, and N-propyl-N-nitro-N-nitrosoguanidine, which induce stomach cancer in rats, decreased the content of pepsinogen isoenzyme 1 )Pg 1), which was separated by poly-acrylamide gel electrophoresis. They also decreased the pepsingoen content of the pyloric mucosa. 4-Nitroguinoline 1-oxide, which induces a low incidence of stomach cancer in rats, rarely decreased the Pg 1 content or the pepsinogen content of the pyloric mucosa, and the incidence of such decreases was not statistically significant. However, diethylnitrosamine and dimethylnitrosamine, which do not induce stomach cancer in rats, did not cause any decrease in pepsinogen content. Ethyl methanesulfonate, a direct-acting carcinogen used as a control, also did not decrease the pepsinogen content.

4-Nitroquinoline-1-oxide↗
PubMed1999

Noninvasive evaluation of Helicobacter pylori therapy: role of fasting or postprandial gastrin, pepsinogen I, pepsinogen II, or serum IgG antibodies.

OBJECTIVE: We evaluated the potential value of a change in serum IgG antibodies, fasting or meal-stimulated gastrin levels, and pepsinogen I (PGI) or pepsinogen II (PGII) levels for identifying Helicobacter pylori (H. pylori) status after antibiotic therapy. METHODS: A total of 32 men and one woman with peptic ulcer disease and documented H. pylori infection were enrolled. Fasting and 30-min postprandial blood samples were obtained at 0, 2, 7, 11, 17, 23, 27, and 39 wk of the study and were analyzed for the factors evaluated. RESULTS: Treatment was successful in 25 patients and failed in seven. Serum IgG antibodies, meal-stimulated gastrin, and both fasting and meal-stimulated pepsinogen I and II levels fell throughout the study, and pepsinogen I:II ratios increased in those whose infection was cured. The mean levels at wk 0 versus wk 7 were: fasting gastrin (fmol/ml) 12.4 and 11, meal-stimulated gastrin 26.5 and 15.4, PGI (ng/ml) 83.7 and 59, PGII (ng/ml) 24.5 and 13.6, PGI/PGII 3.5 and 4.7, and enzyme-linked immunosorbent assay value 4.8 and 4.55. The sensitivity, specificity, and positive and negative predictive values for the data analyzed using different percent changes (e.g., 80%, 50%, and 20%) were calculated. The specificity and sensitivity remained <80% at all time points. CONCLUSIONS: Despite a significant fall in serum markers of H. pylori infection in groups of individuals, no marker tested could be used to reliably determine posttherapy H. pylori status for individual patients.

Adult↗
PubMed1990

Pharmacology of pepsinogen secretion: influence of pentagastrin on pepsinogen secretion in man.

To investigate the effect of pentagastrin on serum and urinary pepsinogens and gastric pepsin, eight healthy male volunteers were studied twice during continuous intragastric perfusion with either NaCl 0.9% or 0.1 M HCl in random order. To the perfusate 3 mg/ml phenol red was added as inert recovery marker. Gastric content was aspirated in 15-minute samples, 4 basally and subsequently 6 during continuous i.v. infusion of pentagastrin 1.5 micrograms/kg/h. Furthermore, serum and urine samples were collected immediately before and after each test. Gastric pepsin output increased after pentagastrin. There were no differences in basal or stimulated pepsin output during saline or HCl perfusion despite marked differences in intra-gastric acidity and acid delivery to the duodenum. In addition, no significant changes in serum pepsinogen levels or urinary pepsinogen excretion were observed after pentagastrin infusion. It is concluded that pentagastrin stimulates gastric pepsin secretion directly, but does not stimulate the release of pepsinogens into the systemic circulation.

Adult↗
PubMed1988

Seminal pepsinogen C is not identical with, but is very similar to gastric pepsinogen C.

Human seminal pepsinogen C has been purified and compared with gastric pepsinogen C. The two zymogens cannot be distinguished by amino acid compositions and sequences of the first 28 N-terminal amino acid residues are identical. Apparent immunological identity is observed with polyclonal antisera. Monoclonal antibodies toward seminal pepsinogen C have been produced. One is able to recognize a non-carbohydrate antigenic determinant only present in seminal pepsinogen C.

Amino Acids↗
PubMed1988

Discrepancies between gastric mucosal and urinary pepsinogen A patterns and in vitro synthesis and secretion of human pepsinogen.

The relationship between electrophoretic pepsinogen A (PGA) patterns from urine and gastric mucosa was studied in healthy volunteers and in patients with various gastric disorders. Discrepancies between urinary and gastric PGA patterns were found in 63.3% of the individuals. In 9% of the subjects with these discrepancies, the phenotype class in urine was different from that in gastric mucosa. The differences were found in all diagnostic groups. The highest frequency of differences was found in patients with gastric ulcer. The differences were not related to the serum PGA level. More than 80% of the differences were caused by a lower relative intensity of pepsinogen A fraction 5 (Pg5) in urine than in gastric mucosa. The possible origin of differences in PGA isozymogen patterns was studied by organ culture of gastric biopsies. In vitro synthesis and secretion of pepsinogens were studied by electrophoresis and autoradiography. The synthesis rate of PGA in biopsies of 1-2 mm diameter was 40-100 ng/hr. Posttranslational modification of PGA isozymogens was demonstrated. Pg2 and part of Pg4 probably are secondary products of Pg3 and Pg5, respectively. In some individuals the secretion rate of Pg3 was low compared to the other isozymogens. The conversion of Pg3 into Pg2 and the differential secretion of the isozymogens may explain some of the discrepancies between gastric and urinary PGA patterns.

Autoradiography↗
PubMed2003

Pepsinogen A, pepsinogen C, and gastrin as markers of atrophic chronic gastritis in European dyspeptics.

Serum levels of pepsinogen and gastrin are parameters that can be used as biomarkers for gastric mucosa. The aim of this study was to validate these serum biomarkers, that is pepsinogen A (PGA), pepsinogen C (PGC), PGA/PGC ratio, and gastrin, as screening tests for precancerous lesions: atrophic chronic gastritis (ACG) or Helicobacter pylori-related corpus-predominant or multifocal atrophy. The study population was comprised of a subsample of 284 patients from the 451 included in the Eurohepygast cohort, between 1995 and 1997. The concentrations of PGA, PGC, and gastrin were measured by radioimmunoassays. Histological diagnosis was the gold standard. Cut-off points were calculated using receiving operator characteristics (ROC) curves. Factors linked to variation of biomarkers were identified using multivariate linear regression. The mean of each biomarker in the sample was: PGA, 77.4 microg x l(-1); PGC, 13.2 microg x l(-1); PGA/PGC, 6.7; and gastrin, 62.4 ng x l(-1). For ACG patients, the areas under the PGA, PGC, PGA/PGC, and gastrin ROC curves were 0.55, 0.62, 0.73, and 0.58, respectively. The best cut-off point for PGA/PGC was 5.6, with sensitivity 65% and specificity 77.9%. For H. pylori-related corpus-predominant or multifocal atrophy, the areas under the respective ROC curves were 0.57, 0.67, 0.84, and 0.69. The best cut-off point for PGA/PGC was 4.7, with sensitivity 77.1% and specificity 87.4%. The results suggested that only the PGA/PGC ratio can be considered as a biomarker for precancerous lesions of the stomach, and may be useful as a screening test.

Antigens, Bacterial↗
PubMed1990

Immunohistochemical studies on the development of cells containing progastricsin (minor pepsinogen) in comparison to prochymosin and pepsinogen in bovine abomasal mucosa.

The localization of progastricsin was studied in cells of abomasal mucosa from cattle of different ages and feeding regimes and compared to the localization of prochymosin and pepsinogen in the same material by use of an immunofluorescence technique with specific rabbit antibodies. Immunoreactivity for progastricsin was first found in calves at the age of about 45 days in surface mucous cells in the pit of the fundic gland. In older calves and adults, mucous neck cells also produced progastricsin. In the pyloric mucosa, on the other hand, traces of progastricsin immunoreactivity were found in the lower base of the pyloric gland even in newborn calves. When the calves grew older, progastricsin-immunoreactive cells also developed in the pit and later in the neck of the pyloric gland; and the number of these cells in this region increased with age. The development of progastricsin-producing cells seemed to be influenced only by age and not by the feeding of milk to the calves. The ontogeny of progastricsin, prochymosin, and pepsinogen exhibited an interesting pattern in cattle, as they started to be produced at three different ages and gave three different patterns of development in the cells of abomasal mucosa. The number of cells producing prochymosin was closely correlated with milk-feeding, while the development of progastricsin was most related to the age of the calf. The most stable factor during the development of the cells in the abomasum was the number of cells producing pepsinogen.

Abomasum↗
PubMed1988

Presence of pepsinogens immunoreactive to anti-embryonic chicken pepsinogen antiserum in fish stomachs: possible ancestor molecules of chymosin of higher vertebrates.

1. Stomachs of adult teleosts and elasmobranchs reacted to an anti-embryonic chicken pepsinogen antiserum (anti-ECPg) as well as to an anti-adult chicken pepsinogen antiserum (anti-ACPg). 2. Zymograms and immunoblots of stomach extracts revealed that anti-ECPg- and anti-ACPg-reactive substances possess peptic activity. 3. The possible relationship between anti-ECPg-reactive pepsinogens in fish and prochymosins in higher vertebrates is discussed.

Animals↗
PubMed1987

Pepsinogen-like immunoreactivity among vertebrates: occurrence of common antigenicity to an anti-chicken pepsinogen antiserum in stomach gland cells of vertebrates.

Stomachs of 14 species selected from five classes of vertebrate were surveyed concerning the reactivity to an anti-adult chicken pepsinogen antiserum (anti-ACPg) with indirect immunofluorescence method. Gland cells of all these stomachs showed reactivity to the antiserum. Crude extract of stomachs from five representatives of mammals, birds, amphibians and fish showed peptic activity (at pH 2.2) of which 70-90% were pepstatin-sensitive. Zymogram and immunoblotting of crude extract revealed that the anti-ACPg-reactive proteins have peptic activity. Molecular weights of anti-ACPg-reactive proteins determined by immunoblotting coincided with the values of purified pepsinogens previously reported for these animals. These results indicate that pepsinogens have been conserved well during vertebrate evolution.

Animals↗
PubMed1997

Influence of pepsinogen gene polymorphisms on serum pepsinogen.

We identified pepsinogen C (PGC) gene polymorphisms by means of PCR, which amplified DNA in the region within the intron between exons 7 and 8, and by 6% polyacrylamide gel electrophoresis. Six alleles were found in a Japanese population. The frequencies of these alleles in 408 unrelated Japanese individuals were 0.074, 0.026, 0.335, 0.237, 0.016 and 0.314, respectively. The serum pepsinogen II level significantly decreased in the order of the allele 6 homozygote, the allele 6 heterozygote and the other genotypes (chi 2 = 7.850, D.F. = 2, p = 0.020). These findings indicated that the genetic background of serum pepsinogen should be considered when screening for stomach cancer by this procedure.

Adolescent↗