SERUM PEPSINOGEN IN THE DIFFERENTIATION OF MEGALOBLASTIC ANAEMIA

Serum pepsinogen levels have been compared in 40 patients with severe megaloblastic anaemia with those obtained from 62 normal subjects, and with levels in 20 patients with pernicious anaemia in remission, 46 patients with iron-deficiency anaemia, and 18 patients with a duodenal ulcer. The range in the normal subjects was 55 to 482 units per ml. It is suggested that a level of below 90 units per ml. should be regarded as indicative of gastric atrophy. It was found to be of value in the early differential diagnosis of severe megaloblastic anaemia. The estimation was found to be reproducible and can be carried out in a routine hospital laboratory.

Purification of pepsinogens from human urine and electrophoretic analysis by caseogram print

Pepsinogen (PG) A and C were purified from human urine, and analyzed by a highly sensitive detection method, "caseogram print". Purification was achieved by a series of conventional chromatographies and FPLC. A relatively large amount (13.2 mg) of PGA was purified from about 20 liters of urine. Purified PGA was separated by a Mono-Q column into each of its isozymogens. The elution order (PGA-5, 4+3, 2) corresponded to the order of electrophoretic migration. Although the concentration of urinary PGC was very low, a trace amount was purified and visualized by electrophoresis. The urinary and mucosal PGCs migrated at the same position, and urinary PGC was detected as two isozymogens similarly to mucosal PGC, suggesting that urinary and mucosal PGCs may be essentially identical.

Helicobacter pylori and hypergastrinaemia during proton pump inhibitor therapy

The rise in serum gastrin and pepsinogen I after 5 days' treatment with the proton pump inhibitor pantoprazole (40 mg/day) was examined in eight duodenal ulcer patients with Helicobacter pylori infection and compared with eight in whom it had been eradicated. Before treatment, the post-prandial serum gastrin concentrations were higher in the H. pylori-positive than -eradicated patients (p less than 0.05). The median rise in pre-prandial serum gastrin concentrations on treatment was similar in the H. pylori-positive (41%) and -eradicated patients (45%). The rise in post-prandial serum gastrin was also similar in the H. pylori-positive (81%) and -eradicated patients (69%), resulting in significantly higher gastrin concentrations during treatment in the former. The median rise in serum pepsinogen I on treatment was greater in the H. pylori-positive (114%) than in the -eradicated patients (8%), resulting in significantly higher concentrations during treatment in the former. These observations indicate that eradication of H. pylori may be a means of moderating the hypergastrinaemia caused by acid-inhibitory therapy. They also indicate that H. pylori-related hypergastrinaemia is not due to an increase of the antral surface pH by the bacterium's urease activity.

[Cigarette smoking and group I pepsinogen levels. Study in a normal population]

Several studies have shown an influence of cigarette smoking on serum pepsinogen group I (PGI) levels in duodenal ulcer patients and in control subjects. The elevation of PGI in smokers has just been interpreted as reflecting some degree of smoking-induced inflammation of the gastric mucosa. We have determined fasting serum PGI by radioimmunoassay in 163 healthy subjects investigated by a survey conducted on a sample population of an urban area in the North-East of Italy by means of a random selection based on the public registers of home addresses. The data reported confirmed that PGI levels are increased by smoking in a healthy population. The main contribution of this study consists in demonstrating in a non-selected population an increase of the only parameter up to date claimed to be a possible serological predictive index for ulcer disease.

Phenylthiocarbamide taste sensitivity in chronic peptic ulcer

Ability to taste phenylthiocarbamide is genetically determined and has been investigated as a possible genetic marker for disease. This study examined phenylthiocarbamide taste sensitivity in gastric and duodenal ulcer disease. The study sample included 164 patients with gastric ulcer, 134 with duodenal ulcer, and 299 community controls. Eight concentrations of phenylthiocarbamide in distilled water were obtained by binary serial dilution. The lowest concentration distinguished by taste from distilled water defined taste threshold. Bimodality of threshold distributions distinguished nontasters from tasters. Comparisons of patients with controls gave odds ratios of nontaste in gastric ulcer and duodenal ulcer of, respectively, 0.7 (P greater than 0.1) and 1.3 (P greater than 0.03). The power of detecting at least a twofold difference between patients and controls in the odds of nontaste was 80%. Nontaste was more common in duodenal than in gastric ulcer patients (odds ratio = 2.0, P = 0.02). Taste sensitivity was unassociated with other genetic factors related to ulcer--ABO blood group, secretor status, and serum pepsinogen 1 level. The difference between gastric and duodenal ulcer patients in the ability to taste phenylthiocarbamide may be genetic; however, this study's inability, despite substantial power, to detect at least a twofold difference between patients and controls suggests that if phenylthiocarbamide taste sensitivity is a genetic factor in peptic ulcer, the relationship is weak.

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.

Renal handling of pepsinogens A and C in man

1. Fractional excretions of pepsinogens A and C in the urine were investigated in 21 healthy subjects and in 38 patients with chronic renal insufficiency. In eight of the healthy subjects fractional excretions were measured again after oral administration of omeprazole for 9 days. 2. The mean fractional excretion of pepsinogen A was 27.6% (range 4.4-73.9%) in healthy subjects and remained unchanged after omeprazole administration. In patients with renal failure the mean fractional excretion of pepsinogen A was 37.9% (range 7.0-81.9%). The mean fractional excretion of pepsinogen C was 1.0% (range 0.04-6.8%) in healthy subjects and decreased after omeprazole. In patients with chronic renal diseases a sharp rise in fractional excretion of pepsinogen C was observed once glomerular filtration rate was less than 40 ml/min. 3. Fractional excretion of pepsinogen A was unexpectedly high for a negatively charged protein with a molecule mass of 40,000 daltons. This might be explained by the presence of the positively charged activation peptide. Furthermore, pepsinogen C seemed to be almost entirely reabsorbed from the glomerular filtrate and a tubular reabsorption maximum appeared to be present. Pepsinogen C may, therefore, be a new marker of tubular function. The cause of the remarkable difference in tubular handling of two quite similar low-molecular-mass proteins remains to be elucidated.

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.

[Pepsinogen I and duodenal ulcer]

In this revision article it was tried to focus on the role played by pepsinogen/pepsin since its discovery until its practical use. Pepsinogen determination as the gastric acid secretion has different basal or stimulated secretion levels in the peptic ulcer, gastritis, etc. The methods for pepsinogen determination are evaluated, verifying that, in spite of radioimmunoassay utilization another methods less sophisticated have been used successfully. The pepsinogen seric levels (PSL) after stimulation with Histalog, discriminate the patients suffering from duodenal ulcer from normal individuals, and they are higher among men than women. A parallelism is made between pepsinogen-I and II finding out pepsinogen-I higher level in smoking individuals. The pepsinogen-I is increased in the duodenal ulcer and II in the gastric ulcer and both of them bent to be characterized as a genetic marker for peptic ulcer. Finally, the main clinical applicability for PSL group I determination is the detection of atrophic gastritis considering its potential for gastric malignancy.

Twin studies on urinary pepsinogen A phenotypes and serum pepsinogen A levels

Urinary pepsinogen A (PGA or PG I) phenotypes and serum PGA levels were studied in MZ and DZ twins and their parents. In 45 out of 48 MZ twin pairs PGA patterns were completely identical, while 3 MZ twin pairs showed minor differences in the relative intensity of the Pg5 isozymogen. This suggests that the intensity of this isozymogen may be influenced by nongenetic factors. There was little difference in the interclass correlations of serum PGA levels between MZ and DZ twins, indicating a large contribution of common environmental factors to serum PGA levels. This is in contrast with previous studies.

New detection method for uropepsinogen (PGA) using isoelectric focusing and immunoblotting techniques

Uropepsinogen (PGA) was isolated and purified from human urine using a column chromatography series. The purified PGA was injected into a rabbit and a PGA-specific antibody was obtained. PGA isozymogen in human urine could be detected reproducibly by immunoblotting using this antibody after isoelectric focusing electrophoresis (IEF) on polyacrylamide gels. This technique may prove to be useful in the genetic study of PGA polymorphism.

Newly characterized genetic polymorphism of uropepsinogen group A (PGA) using both isoelectric focusing and immunoblotting

Genetic polymorphism of uropepsinogen group A (PGA) was characterized in human urine using a technique involving both polyacrylamide gel isoelectric focusing and immunoblotting with an anti-PGA antibody. PGA was clearly separable into five fractions, termed I to V in order of decreasing anodal mobility. The most slowly migrating fraction V was composed of F (fast) and/or S (slow) band(s). The population frequencies of the three patterns of fraction V (F, FS, and S) and family studies indicated that PGA V is controlled by a pair of alleles, PGA V*F and PGA V*S, at a single autosomal locus, and that both are codominant. The frequencies of the genes are 0.07 for PGA V*F and 0.93 for PGA V*S.

[Role of serum pepsinogen I values in primary duodenal ulcer in childhood]

Serum pepsinogen I (PGI) was measured by radioimmunoassay in the fasting state in three homogeneous family groups composed of parents and their children. Group 1, families, did not suffer from primary duodenal ulcer (PDU). Group 2, 10 families had at least one parent with PDU diagnosed endoscopically. Group 3, 6 families, had at least one child with PDU and one parent with PDU diagnosed endoscopically. The analysis of variance (ANOVA) of PGI in the examined children, showed a significant difference between the three groups (F = 22.83; p = 0.005). In all 3 groups the ANOVA of serum PGI of the fathers and the mothers were significantly different: fathers (F = 4.4; p = 0.241); mothers (F = 3.4; p = 0.05). A correlation was noted between PGI of the fathers and PGI of the children (r = 0.31; p = 0.05); but a more significant correlation was observed between PGI of the mothers and PGI of the children (r = 0.48; p = 0.001). In group 3, the correlation between PGI of the mothers and PGI of the children was striking (r = 0.89; p = 0.025). However, the PGI of the fathers and the PGI of the children were not different in this group (r = 0.27; p = n.s.). The multiple correlation between PGI of the children and PGI of both parents was significant (r2 = 0.316). In group 3, the correlation was very high between the mothers and the children (r2 = 0.81).

Isolation of human, swine, and rat prepepsinogens and calf preprochymosin, and determination of the primary structures of their NH2-terminal signal sequences

The total RNAs were extracted from human, swine, rat, and calf gastric mucosae, and translated in vitro in the presence of radiolabeled amino acids using a wheat germ cell-free system. Upon sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis of the translation products, a protein band with a molecular weight of about 43,000 was obtained in each case as one of the major products. These products could be specifically immunoprecipitated with a corresponding anti-pepsinogen or anti-chymosin antiserum. Radiosequence analysis of these translation products purified by SDS-polyacrylamide gel electrophoresis showed that each of them is a precursor form, i.e., prepepsinogen or preprochymosin, having an amino-terminal extension peptide (signal sequence) comprising 15 (human and swine) or 16 (rat and calf) amino acid residues. The primary structures of these signal sequences were determined to be as follows: (Sequence: see text). These signal sequences share common characteristics with those of other pre-secretory proteins, i.e., the presence of positive charges in the NH2-terminal region, hydrophobic amino acid clusters in the interior part, and amino acids with short side chains at the site of cleavage by the signal peptidase.

Human uropepsinogen is a new human pepsinogen proisozyme

The first 20 amino acid residues of human uropepsinogen has been determined to be H2N-Ile-Met-Tyr-Lys-Val-Pro-Leu-Pro-Ile-Lys-Lys-Ile-Leu-Val Val-Pro-Leu-Ile-Val-Tyr-Met. Comparison with the sequence of human stomach pepsinogen shows that these proteins are isozymes. Comparative sequence data are presented and discussed.

Measurement of plasma group I pepsinogens

Plasma group I pepsinogen (PG I) concentration is now a readily available non-invasive marker of gastric secretory function, with several potentially useful applications. Ninety-eight percent of control subjects had a plasma PG I below 115 ng/ml while values above this level were seen in 43% of duodenal ulcer patients. Plasma PG I levels below the observed normal lower limit of 30 ng/ml were seen consistently in patients with documented achlorhydria or pernicious anaemia. In 48 patients with a variety of upper gastrointestinal disorders there was a significant correlation between PG I pepsinogens and pentagastrin-stimulated maximal acid output. Changes in plasma PG I promise to be useful in evaluating both operations on the vagus and newer anticholinergic drugs, whilst in epidemiological and family studies these measurements seem well suited to explore duodenal ulcer heterogeneity.

Group I pepsinogens in serum. I. Normal range, age and sex relation, diurnal rhythm, seasonal variation, and distribution in ABO blood groups

The concentration of group I pepsinogens (PG I) in serum was determined in 235 healthy persons and hospital controls. The concentration was significantly higher in males. Correction of PG I with regard to body weight or lean body mass eliminated the sex difference but not the weak correlation with age. The normal range was 0.60-3.3 ng PG I/ml serum/kg body weight. For comparison with other PG I studies another normal range, 46-211 ng PG I/ml serum, was calculated as the 95% interpercentile range of the present PG I concentrations. In a study of diurnal rhythm and in a 6-month study of seasonal variation, no significant variation of PG I in serum was found. Serious non-gastric surgical disease did not influence the PG I level in serum. The PG I levels in blood groups O, A, and B did not differ significantly.

Serum pepsinogen I and the state of gastric mucosa in an Estonian population sample

Seventy-seven adult subjects from a rural population were examined by gastroscopic biopsy and serum pepsinogen I (PG I) determination. A new radioimmunoassay method for PG I determination, based on enzymatic iodination and the double antibody solid-phase technique, was used. A highly significant correlation (r = 0.488, p less than 0.001) between the state of the fundal mucosa and the PG I level was observed. In persons with severe or moderate forms of atrophic fundal gastritis the PG I values were notably lower than those of the other groups. Good differentiation of persons with normal fundal mucosa and with severe fundal gastritis was obtained. In subjects with a normal fundal mucosa the PG I values were significantly higher in men (130 +/- 48 micrograms/l) than in women (87 +/- 17 micrograms/l). A decline in serum PG I level with age was observed. In patchy gastritis the PG I value is helpful in assessing the state of the fundal mucosa.