The Effect of Renal Replacement Therapies on Serum Gastrointestinal System Hormones

Background. The kidney is a major site for the inactivation, degradation, and clearance of a variety of peptide hormones. It has been shown that the uremia increases or decreases gastrointestinal system (GIS) hormones. Moreover, studies investigating the serum GIS hormones levels in chronic renal failure (CRF) were conducted mainly in a particular period of the renal replacement therapy, and the changes caused by continuous ambulatory peritoneal dialysis (CAPD) and hemodialysis (HD) could not be fully demonstrated. In this study, we investigated the effect of CAPD and HD on serum GIS hormones (amylase, lipase, trypsinogen, and gastrin) levels in CRF patients who were diagnosed for the first time. Methods. Serum amylase, lipase, trypsinogen, and gastrin levels were measured in 36 patients who were just diagnosed with CRF, 22 patients with CAPD and 14 patients with HD. GIS hormones of these patients were measured before treatment and three months from the beginning of CAPD and HD treatment. As the control group, 20 normal healthy cases with well-matched age and gender were used. Results. The mean serum amylase, lipase, secretin, and gastrin levels were found meaningfully decreased according to the beginning values at third months of the CAPD and HD treatment. However, they were higher than control group. Conclusion. In patients receiving CAPD or HD as renal replacement therapy, GIS hormone levels were found to be lower, albeit higher than the healthy control group.     

K-ras and B-raf gene mutations are not associated with gastrin- and CCK2-receptor mRNA expression in human colorectal tumour tissues

BACKGROUND: Colorectal cancer is a multistep process caused by genetic alterations in cell growth regulatory genes such as K-ras and B-raf. It has been assumed that mutations in the K-ras gene induce gastrin gene expression and that gastrin stimulates the growth of colorectal cancer in an autocrine fashion by coexpressing gastrin and cholecystokinin (CCK)2 receptors. The aim of this study was to examine a possible association of K-ras and B-raf gene mutations with gastrin and CCK2 receptor mRNA expression in human colon and rectum tumour biopsy specimens. METHODS: K-ras and B-raf gene mutations as well as gastrin and CCK2 receptor mRNA expression in 50 colon and 46 rectum biopsies, respectively, were determined using molecular biology methods. RESULTS: K-ras mutations occurred in 44% colon and 30% rectum and B-raf mutations in 16% colon and 4% rectum tumours, respectively. Gastrin mRNA was expressed in 64% colon and 61% rectum tumours, whereas CCK2 receptor mRNAs was expressed in 32% colon and 13% rectum tumours. K-ras or B-raf gene mutations and simultaneous gastrin mRNA expression was observed in 40% colon and 17% rectum tumours, respectively. Co-expression of gastrin and CCK2 receptor mRNA occurred in 20% colon and 9% rectal tumours. CONCLUSIONS: The results do not support the hypothesis that K-ras and B-raf gene mutations have an impact on gastrin- and CCK-receptor mRNA expression in colorectal tumour tissues.     

Effects of dietary protein alterations on circadian rhythms of gastrointestinal peptides in rats

Altered protein diets and circadian rhythms of gastrin and cholecystokinin (CCK) were investigated in 126 male and 126 female Sprague-Dawley rats acclimated for two weeks to a 1212 hr lightdark cycle. Rats were divided equally and fed low-protein (8%), high-protein (64%) or normal protein (27%) diets for four weeks. All animals were fasted for 24 hr prior to blood collections. Blood samples were collected at 4-hr intervals for 24 hr for determination of plasma gastrin and CCK using specific radioimmunoassays. A significant rhythm for gastrin was detected in males on normal and lowprotein diets (P < 0.03) and in females on lowprotein diets (P < .02). A significant rhythm for CCK was detected (P < 0.05) in rats of both sexes fed normal and highprotein diets. Mean plasma levels of both peptides were lower in females than males. In a separate study, food intake and body weight were monitored in male rats receiving the three diets over 21 days. Animals on the lowprotein diet exhibited reduced food intake and body weight compared to rats fed the normal or high-protein diets.Presented in part at the Eighteenth International Conference on Chronobiology, Leiden, The Netherlands, July 12–17, 1987.Supported by a grant from the National Institutes of Health PO1 DK35608.     

悬灸足三里对疳积大鼠胃泌素和胃动素及体重的影响

[目的]探讨艾灸足三里治疗疳积的作用机制.[方法]SD大鼠40只,随机分为正常组、模型组、对照组(非经穴治疗)、治疗组,采用特制高脂肪、高热量饲料喂养造模.造模后,艾灸足三里治疗.[结果]造模后大鼠进食量、体重、血清胃泌素(GAS)、胃动素(MOT)均降低,与正常组比较差异有统计学意义(P＜0.01).经2个疗程治疗后接近正常水平,与正常组比较差异无统计学意义.[结论]艾灸足三里能提高疳积大鼠的进食量、体重及血中GAS、MOT水平,从而明显改善其低下的消化功能.     

胃泌素及其受体拮抗剂对BGC－823细胞系生长的调节

本文用液闪测定和细胞计数观察了胃泌素及其受体拮抗剂丙谷胺和Ｌ－３６５２６０对体外培养的人胃腺癌ＢＧＣ－８２３细胞系的生长调节作用。结果表明不同浓度胃泌素对ＢＧＣ－８２３细胞系的生长均有显著促进作用，而这种作用可被其受体拮抗剂丙谷胺和Ｌ－３６５２６０所抑制，且发现在胃泌素浓度衡定时，Ｌ－３６５２６０对ＢＧＧ－８２３细胞系的生长抑制作用明显强于丙谷胺。这一结果也提示，Ｌ－３６５２６０对胃泌素受体的亲合力可能明显高于丙谷胺。     

Adaptive changes of the enterochromaffin and gastrin cells in the rat gastrointestinal tract following subtotal colectomy

Objective. Colectomized patients often have diarrhoea and increased gastric acid secretion. Although serotonin influences gastrointestinal (GI) motility and secretion, GI serotonin-producing enterochromaffin (EC) cells have not been investigated after colectomy, nor have the antral gastrin cells. The aim of this experimental study was to investigate the GI tract in rats 8 weeks after subtotal colectomy, with particular emphasis on the frequency and distribution of EC and gastrin cells. Material andmethods. Immunohistochemical techniques were used to identify the two endocrine cell types. Results. The colectomized animals had diarrhoea. Body-weight was lower and the small intestine shorter in the colectomized animals compared with sham-operated and untreated controls. In the two surgically treated groups, the antral mucosa was thinner and the small intestinal mucosa was thicker compared with that of the untreated rats, whereas the thickness of the rectum of the colectomized rats was increased compared with that of the control groups. In the colectomized animals, the number of EC cells was increased in the small intestine and rectum, whereas the numbers of both EC and gastrin cells were decreased in the antrum. Conclusions. The results indicate that colectomy exerts a significant influence on the GI mucosa and on the endocrine cell systems studied. An increased number of EC cells can result in alterations in motility and secretion, which may be important in the pathogenesis of the diarrhoea that often occurs after colectomy.     

Treatment of type I gastric neuroendocrine tumors with somatostatin analogs

Background and Aim: There are limited data on response and long‐term follow‐up of octreotide therapy in type‐I gastric neuroendocrine tumors. The objective of the present study was to assess the response of type‐I gastric neuroendocrine tumors to octreotide‐long acting, repeatable (LAR) therapy and evaluate long‐term follow up of such patients after therapy. Methods: Three patients with documented type‐I gastric neuroendocrine tumors from a tertiary gastroenterology centre were studied. Octreotide‐LAR therapy 20 mg intramuscularly every 28 days was administered for one year. Serum gastrin and chromogranin levels, gastroscopies and biopsies from tumor nodules at 6 months and one year on therapy and every 6 months after completion of drug therapy were taken. Follow‐up after completion of therapy extended for 3 years in two and 2.5 years in one patient. Results: During octreotide therapy there was normalization of serum gastrin levels and serum chromogranin levels. Tumors in all three patients had regressed at 6 months of treatment. Following cessation of therapy, there was progressive rise of serum gastrin to pre‐treatment levels. Serum chromogranin levels remained within normal limits. Gastroscopic and histologic examination of gastric biopsies did not reveal recurrence of tumors in any patients. All patients tolerated therapy well and became asymptomatic soon after drug therapy. Conclusions: Octreotide‐LAR therapy causes regression of type‐I gastric neuroendocrine tumors. After completion of drug therapy there was no recurrence of tumors even with continued hypergastrinemia. Octreotide therapy should be considered as one of the treatment options in such patients.     

Polymorphism in the C-reactive protein (CRP) gene affects CRP levels in plasma and one early marker of atherosclerosis in men: The Health 2000 Survey

The gastrointestinal hormone gastrin is measured in plasma in physiological, pathophysiological and diagnostic investigations. In the diagnosis of hypergastrinaemic diseases such as gastrinomas and gastric achlorhydria, measurement of gastrin concentrations in circulation is crucial. Gastrin circulates, however, not as a single peptide but as a mixture of peptides of different lengths and amino acid derivatizations. Moreover, in hypergastrinaemia the peptide pattern changes. Consequently, diagnostic gastrin measurements require immunoassays that recognize the pathological plasma patterns, which are characterized by a predominance of the large peptides (gastrin‐34 and gastrin‐71) and less, if any, of the shorter main form of gastrin in normal tissue, gastrin‐17. Alternatively, and in specific cases, “processing‐independent assays” (PIA) for progastrin may be considered, since hypersecreting gastrin cells also release substantial amounts of biosynthetic precursors and processing intermediates. Recently, gastrin kits that do not take the pathological plasma patterns into account have been marketed and may miss the diagnosis. Therefore, proper diagnosis of gastrinomas and other hypergastrinaemic diseases requires insight into cellular gastrin synthesis and peripheral metabolism, and also into the design of useful immunoassays. This review discusses the art of measuring gastrin in plasma with adequate diagnostic specificity.     

Pentapeptide Infusion Test

Pentapeptide infused intravenously in graded doses provoked at a dose of 1.5 μg per kg per hour a peak HCl output, which was significantly higher than the HCl secretion induced by intravenous histamine in a dose of 40 μg per kg per hour in five healthy subjects. Pentapeptide infusion test at a dose of 1.5 μg per kg per hour appears to be a very reproducible and safe mode of gastric stimulation, giving a sustained and high level of gastric secretion in 20 subjects, including 10 healthy men and 10 duodenal ulcer patients. Infusion test with pentapeptide has some advantage over histamine stimulation in so far as it is safe, and almost completely free of side-effects. No difference in the response curves to pentapeptide and histamine was found between the normal subjects and duodenal ulcer patients.