Ko Tanaka

β-Endorphinlike immunoreactivity and somatostatinlike immunoreactivity in normal gastric mucosa, muscle layer, and adenocarcinoma

beta-Endorphinlike immunoreactivity and somatostatinlike immunoreactivity were detected in the mucosa and muscle layer of normal gastric antrum and corpus and in moderately differentiated adenocarcinoma derived from the antral mucosa. The concentration of beta-endorphinlike immunoreactivity in the normal gastric tissues was 4-15 pmol/g wet wt tissue; this value varied from 9.64 to 241.39 pmol/g wet wt tissue (81.38 +/- 37.82 pmol/g wet wt tissue) in adenocarcinomas. The concentration of somatostatinlike immunoreactivity was 18-25 pmol/g wet wt tissue in normal gastric mucosa, whereas it was 1-2 pmol/g wet wt tissue in adenocarcinomas. Gel exclusion chromatography of beta-endorphinlike immunoreactivity revealed two peaks corresponding to beta-endorphin and beta-lipotropin. In normal mucosa and in the whole layer of antrum, the major peak was eluted near the position of beta-lipotropin, and the minor broad peak was eluted near the position of beta-endorphin. In contrast, in adenocarcinoma, beta-endorphinlike immunoreactivity was eluted broadly at the position of beta-endorphin and the other smaller peak was at the position of beta-lipotropin. Gel exculsion chromatography of somatostatinlike immunoreactivity also showed different patterns between antral mucosa and adenocarcinoma. This study revealed the presence of the opioid peptide, beta-endorphinlike immunoreactivity, not only in normal gastric tissue but also in adenocarcinomas with highly increased concentration and different elution patterns in combination with decreased concentration of somatostatinlike immunoreactivity.

The measurement of Ascaris suum protein by radioimmunoassay in sera from patients with helminthiasis and with gastrointestinal diseases.

In this study, we have developed a reliable radioimmunoassay (RIA) for Ascaris suum protein (Asp) and have measured the serum concentration of Asp in control subjects and in patients with helminthiasis and a variety of gastrointestinal diseases. The cross-reactivities of Asp antibody with other helminth worm antigens were also measured by RIA. Ascaris lumbricoides contained approximately the same amount of Asp antigenic substance as did Ascaris suum. Toxocara canis had a high concentration of a substance partially cross-reactive with Asp. Small amounts of substance cross-reacting with Asp were also exhibited by Anisakis larvae, Schistosoma japonicum and Taenia saginata. However, no cross-reactivities of Fasciola hepatica and Paragonimus westermani with Asp were observed in this study. Almost all the serum levels of Asp from normal control subjects were below the sensitivity of this RIA (10 ng/ml). High concentrations of Asp were observed in sera from patients with ascariasis (64.5 +/- 18.8 ng/ml: mean +/- S.E.), anisakiasis (75.2 +/- 28.0 ng/ml), toxocariasis (78.4 +/- 31.3 ng/ml) and schistosomiasis japonica (14.3 +/- 3.4 ng/ml). Asp levels in sera from patients with other helminthiasis were not significantly high. From these findings, it was suggested that RIA for Asp may not be specific for diagnosis of ascariasis, but might be a suitable screening method for patients with some kinds of helminthiasis. Interestingly, high concentrations of Asp were also observed in sera from patients with ulcerative colitis (24.8 +/- 2.5 ng/ml) and Crohns disease (19.8 +/- 5.2 ng/ml), but Asp levels from 7 other gastrointestinal diseases seemed not to be significantly high. These findings remain unexplained but may derive from cross-reactivities between helminthic and gut mucosal antigens.

Effect of Zinc Ion on Human Chorionic Gonadotropin-Stimulated in Vitro Production of Cyclic AMP and Testosterone by Rat Testis

Summary: This study explores the effects of several divalent metal ions on the in vitro production of cyclic AMP, cyclic GMP, and testosterone by rat testicular tissue and on the amount of binding of [125I]human chorionic gonadotropin (hCG) in the testis. Zn2+ at concentrations of 10-6 to 10-4 M enhanced the hCG-stimulated production of cyclic AMP and testosterone, but only in the presence of Ca2+. [125I]hCG binding to rat testicular tissue was not affected by Zn2+. Cu2+, Ni2+, Co2+, and Mn2+ did not increase cyclic AMP or testosterone production in concentrations of 10-7 to 10-3 M and even inhibited them at a high concentration (10-2 M). Cyclic GMP production was not affected by these divalent ions. These results suggest that Zn2+ may play an important role in rat testicular steroidogenesis.

Development of antral gastrin-like immunoreactivity and pituitary CCK8/gastrin-like immunoreactivity in rats

Gel filtration of antral extract of adult rats revealed gastrin-17 and gastrin-34. Gel filtration of anterior pituitary extract showed CCK8 and gastrin-17, whereas posterior pituitary extract showed only a CCK8. Antral gastrin-like immunoreactivity (G-LI) increased after milk feeding and especially after weaning was started. Changes in diet may exert a profound influence on the ontogenic development of antral G-LI, but not pituitary CCK8/G-LI.

Influence of diet on the development of gastrin- and somatostatin-like immunoreactivity in the stomach of rats

The effects of changes in diet on antral gastrin-like immunoreactivities and antral and corporal somatostatin-like immunoreactivities were studied in three groups of young male rats. Group 1 rats were weaned physiologically, group 2 rats received only breast milk, and group 3 rats were fed milk until 20 days of age and then were switched abruptly to laboratory chow. In group 1, antral gastrin-like immunoreactivity and somatostatin-like immunoreactivity increased gradually from 13 days of age to adults. In group 2, antral gastrin-like immunoreactivity did not increase, and antral and corporal somatostatin-like immunoreactivity increased until 20 and 25 days of age, respectively. In group 3, there were three- to fivefold increases of antral gastrin-like immunoreactivity and somatostatin-like immunoreactivity after changing to laboratory chow. Dietary changes had no effect on the concentration of corporal somatostatin-like immunoreactivity. These results suggest that the developmental patterns of gastric gastrin-like immunoreactivity and somatostatin-like immunoreactivity are closely related to diet; laboratory chow may play an important role in the development of these gut hormones.

Effect of cisapride on the concentrations of β-endorphinlike immunoreactivity and substance P-like immunoreactivity in the rat gastrointestinal tract

Cisapride is a gastrointestinal prokinetic agent reported to be devoid of direct cholinergic effect from the myenteric plexus of the gut. The effect of cisapride (0.125, 0.5, 2mg/kg, i.p.) on the concentration beta-endorphin and substance P in rat gastrointestinal tract was studied. beta-Endorphinlike immunoreactivity contents were significantly increased in both mucosal and muscular layers of the entire gastrointestinal tract (from gastric body to rectum) of the rats treated with 2 mg/kg of cisapride. beta-Endorphinlike immunoreactivity contents were also increased in a part of the gastrointestinal tract of the rats treated with 0.125 or 0.5 mg/kg of cisapride. Substance P like immunoreactivity contents were significantly decreased in muscular layers of the rectosigmoid colon of the rats treated with 2 mg/kg of cisapride. This study suggests that the prokinetic effects of cisapride may relate to the contents of beta-endorphinlike immunoreactivity and substance P like immunoreactivity in gastrointestinal tract.