An immunohistochemical study of the gastrointestinal endocrine cells in the C57BL/6 mice

The regional distributions and relative frequencies of some gastrointestinal endocrine cells in the eight portions (fundus, pylorus, duodenum, jejunum, ileum, cecum, colon and rectum) of the gastrointestinal tract of C57BL/6 mouse was studied with immunohistochemical method using seven types of specific anti-sera against chromogranin A (CGA), serotonin, somatostatin, human pancreatic polypeptide (HPP), glucagon, gastrin and cholecystokinin (CCK)-8. In this study, all these seven types of immunoreactive (IR) cells were identified. Most of these IR cells in the intestinal portion were generally spherical or spindle in shape (open-type cell) while cells showing round in shape (closed-type cell) were found in the intestinal gland and stomach regions occasionally. Their relative frequencies were varied according to each portion of gastrointestinal tract. CGA-IR cells were demonstrated throughout the whole gastrointestinal tract and they showed most predominant in the pylorus and duodenum. Serotonin-IR cells were detected throughout whole gastrointestinal tract and they showed highest frequency in the stomach and colon. Somatostatin-IR cells were demonstrated throughout whole gastrointestinal tract except for large intestine and showed highest frequency in the fundus. HPP-IR cells were found in the fundus with rare frequency. Peculiarly, glucagon-IR cells were restricted to the fundus, ileum and colon with a few frequencies. Gastrin-IR cells were restricted to the pylorus with numerous frequency and CCK-8-IR cells were observed in the pylorus, duodenum and jejunum with numerous and/or a few frequencies, respectively. In conclusion, some peculiar distributional patterns of gastrointestinal endocrine cells were found in C57BL/6 mouse.     

An immunohistochemical study of gastrointestinal endocrine cells in the BALB/c mouse

The distributions and frequencies of some endocrine cells in the eight portions of the gastrointestinal tract (GIT) of BALB/c mouse were studied. Endocrine cells were stained using immunohistochemical method with seven types of antisera against bovine chromogranin (BCG), serotonin, gastrin, cholecystokinin (CCK)-8, somatostatin, glucagon and human pancreatic polypeptide (HPP), and the regional distributions and their relative frequencies were observed in the eight portions of the GIT of BALB/c mice. All seven types of immunoreactive (IR) cells were identified. Most of the IR cells in the intestinal portion were generally spherical or spindle in shape (open type cell) while round-shaped cells (closed type cell) were found in the intestinal gland and stomach regions occasionally. Their relative frequencies varied according to each portion of the GIT. BCG-IR cells were observed throughout the whole GIT except for the rectum and they were most predominant in the pylorus. Serotonin-IR cells were detected throughout the whole GIT and they showed the highest frequency in the fundus. Gastrin- and CCK-IR cells were restricted to the pylorus and duodenum with a majority in the pylorus and rare or a few frequencies in the duodenum. Compared with other mammals, somatostatin-IR cells were restricted to the fundus and pylorus with a few frequencies, respectively. In addition, glucagon- and HPP-IR cells were restricted to the fundus and duodenum, respectively, with relative low frequencies. Some species-dependent unique distributions and frequencies of endocrine cells were observed in the GIT of BALB/c mouse compared with other rodents.     

The regional distribution and relative frequency of gastrointestinal endocrine cells in SHK-1 hairless mice: an immunohistochemical study

The regional distributions and relative frequencies of some gastrointestinal endocrine cells in the eight portions (fundus, pylorus, duodenum, jejunum, ileum, caecum, colon and rectum) of the gastrointestinal tract of SKH-1 hairless mice were investigated using immunohistochemical methods and seven types of specific antisera against somatostatin, serotonin, glucagon, cholecystokinin (CCK)-8, secretin, pancreatic polypeptide (PP) and gastrin. In this study, somatostatin-, serotonin-, glucagon-, CCK-8-, secretin- and gastrin-immunoreactive (IR) cells were identified. Most of these IR cells in the intestinal portion were generally spherical or spindle-shaped (open-type cell) while cells that were round in shape (close-type cell) were occasionally found in the stomach regions. Their relative frequencies were varied according to each portion of gastrointestinal tract. Somatostatin-IR cells were found throughout the gastrointestinal tract except for the large intestine. Serotonin-IR cells were detected throughout the whole gastrointestinal tract and were the most predominant endocrine cell types in this species of mouse. Glucagon-IR cells were restricted to the fundus, occurring rarely. CCK-8-IR cells were observed in the pylorus, duodenum and jejunum with frequencies that were numerous, moderate and few, respectively. Peculiarly, secretin-IR cells were demonstrated in the whole intestinal tract with either few or rare frequencies. Gastrin-IR cells were restricted to the pylorus and were numerous. However, no PP-IR cells were found in this study. In conclusion, some peculiar distributional patterns of gastrointestinal endocrine cells were found in SKH-1 hairless mouse.     

An immunohistochemical study of the gastro-entero-pancreatic endocrine cells in the alimentary tract of the Korean tree squirrel, Sciurus vulgaris corea.

The regional distribution and relative frequencies of gastrointestinal endocrine cells were studied immunohistochemically in the gastrointestinal mucosa of Korean tree squirrels. Seven kinds of endocrine cells were identified in this study. Although a large number of 5-hydroxytryptamine-immunoreactive cells were seen throughout the gastrointestinal tract, they were most predominant in the duodenum. A moderate number of glucagon-immunoreactive cells which were restricted to the cardia and fundus of the stomach was also observed. Bovine chromogranin-immunoreactive cells were numerous in the cardia and pylorus of the stomach, found in moderate numbers in the fundus, duodenum and large intestine, but rare in the jejunum. Porcine chromogranin-immunoreactive cells were found in moderate numbers in the stomach but were rare in the duodenum. Gastrin/cholecystokinin-immunoreactive cells were abundant in the pyloric gland region but scarce in the duodenum. Bovine pancreatic polypeptide-immunoreactive cells were observed to be rare and found only in the pyloric gland region. Somatostatin-immunoreactive cells were distributed moderately in the stomach but were few in number in the intestine. No insulin-immunoreactive cells were found in the gastrointestinal tract of Korean tree squirrels. These results suggest that although the Korean tree squirrel is a herbivorous rodent, the distribution pattern of its gastro-entero-endocrine cells is rather similar to that reported for omnivorous animals.     

An immunohistochemical study of endocrine cells in the alimentary tract of the red-bellied frog, Bombina orientalis

The regional distribution and relative frequency of endocrine cells was studied immunohistochemically (PAP method) in the alimentary tract of the red-bellied frog, Bombina orientalis, using antisera against serotonin, somatostatin, chromogranin (CG), cholecystokinin (CCK)-8, bombesin, secretin, glucagon and pancreatic polypeptide (PP). Eight kinds of endocrine cells were identified in this study. These immunoreactive cells were located in the gastric glands of the stomach regions and in the intestinal or esophageal epithelium with variable frequencies. They were spherical or spindle-shaped. Serotonin- and somatostatin-immunoreactive cells were demonstrated in the whole alimentary tract including esophagus. CG-immunoreactive cells were restricted to the stomach. CCK-8-immunoreactive cells were observed from the antrum to the ileum. Bombesin-immunoreactive cells were restricted to the stomach. Secretin-immunoreactive cells were demonstrated in the pylorus, duodenum and ileum. Glucagon-immunoreactive cells were found in the antrum and duodenum. PP-immunoreactive cells were detected from the antrum to the rectum. In conclusion, throughout the alimentary tract of the red-bellied frog, the different regional distribution and relative frequency of endocrine cells were demonstrated. The regional distributions and relative frequencies of the endocrine cells in the alimentary tract of the red-bellied frog were resembled to those of the other anuran species except for esophagus.     

莱芜黑山羊胃肠道血管活性肠肽免疫反应阳性细胞的研究

比较观察血管活性肠肽(VIP)在莱芜黑山羊胃肠道内的分布,用免疫组织化学方法显示胃肠壁各层及各肠段的分布情况。结果表明,血管活性肠肽以贲门部数量最多,结肠、空肠、幽门、盲肠、直肠、胃底次之,十二指肠、回肠、食管中未发现VIP细胞。VIP细胞形态多样,呈椭圆形和锥体形,常有突起伸至其他细胞附近,也有突起直达上皮表面。     

断奶仔猪胃肠道中IgA和IgG分泌细胞的分布

本研究旨在探讨IgA和IgG分泌细胞在断奶仔猪胃肠道不同部位的分布特点和规律。选取8头断奶24 d的仔猪,采集胃底部、胃体部、胃幽门部、十二指肠、空肠、回肠和结肠组织样品,应用免疫组织化学方法检测胃肠道中IgA和IgG分泌细胞的变化。结果显示:IgA和IgG分泌细胞在胃肠道中具有类似的分布特点和规律,即2种分泌细胞主要分布在黏膜固有层中,其数量沿着胃肠道呈现先增加后减少的趋势,其中IgA和IgG分泌细胞在胃幽门部和小肠分布最多。结果表明仔猪的胃幽门部和小肠前段可能是发挥黏膜免疫反应和抵御外界病原微生物入侵的重要位点。     

Distribution of 5-hydroxytryptamine,Ghrelin or Glucagon-like Peptide-1 Immunopositive Cells in the Gastrointestinal Tract of Meihua Pig

In order to analyze the distributions and densities of endocrine cells in the gastrointestinal tract of Meihua pig (an elite native breed of Guangdong province, China), 6 healthy piglets weaned at 30 days of age were fed with the same diet till 65 days of age. At 65 days of age, different sections of the gastrointestinal tract of each piglet were collected, and the features and densities of 5-hydroxytryptamine (5-HT), ghrelin and glucagon-like peptide-1 (GLP-1) immunopositive cells were detected by immunohistochemistry. The results showed that the 5-HT positive cells distributed at the epithelial layer throughout the intestinal tract (duodenum, jejunum, ileum and colon) with a variety of features (e.g. cone, round, spindle), and they could be classified into either open-shape or closed-shape type, the density of 5-HT positive cells in duodenum was highest; The ghrelin positive cells were located along the gastrointestinal tract (gastric glands, pylorus, duodenum and jejunum) with both open-shape and closed shape, and its density decreased along the tract with most cells in gastric glands; The GLP-1 positive cells were observed along the intestinal tract, but its density increased from duodenum to ileum and then decreased in colon. This study might provide supporting data for further study of the gastrointestinal physiology of Meihua pig.     

梅花猪胃肠道5-羟色胺、胃饥饿素和胰高血糖素样肽-1免疫阳性细胞分布特征研究

为了解中国优良地方猪种梅花猪胃肠道内分泌细胞的分布与形态特征,本试验选取6头30日龄断奶健康梅花仔猪,在相同条件下饲养至65日龄,所有仔猪饲喂相同日粮,自由采食饮水。试验结束时,收集仔猪胃肠道各段组织样品,应用免疫组织化学方法观察3种胃肠道内分泌激素5-羟色胺（5-HT）、胃饥饿素（ghrelin）和胰高血糖素样肽-1（GLP-1）免疫阳性细胞的分布及形态特征,并对阳性细胞密度进行分析。结果显示,梅花猪的肠道不同部位（十二指肠、空肠、回肠和结肠）均存在5-HT阳性细胞,主要位于肠上皮组织中,呈锥形、圆形、梭形等形态,可分为开放型和闭合型,其中十二指阳性细胞肠密度显著高于其他肠段（P<0.05）;梅花猪的胃肠道不同部位均有Ghrelin阳性细胞,阳性细胞密度也是随胃肠道走向递减,胃腺体部密度最高;梅花猪的肠道不同部位均有GLP-1阳性细胞,阳性细胞密度沿肠道走向呈抛物线分布,其中回肠数量最多。本试验结果为进一步探究梅花猪胃肠道生理奠定了基础。     

Computed tomographic findings of the gastrointestinal tract in rabbits

BackgroundGastrointestinal (GI) diseases are common in rabbits. Although diagnostic imaging studies can assist clinicians in selecting therapeutic approaches, there are few reports of advanced imaging findings in normal rabbits. Computed tomography (CT) is recognized as a useful tool in dogs and cats, but there are few reports of normal findings on multidetector computed tomography (MDTC) in rabbits. The goals of this study are to describe the CT anatomic imaging appearance of the GI tract and their normal variation in healthy pet rabbits and to obtain the normal wall thickness measurements of normal GI tract structures.MethodsTwenty-three rabbits were scanned under general anesthesia and the CT abdominal images were analyzed by two experienced radiologists. Location and size of the major GI organs and structures were determined, and wall thickness of the stomach, small and large intestines were measured, including the interobserver agreement. Statistical analysis of quantitative and qualitative variables was performed.ResultsWall thickness values were established for the different parts of the stomach (cardia: 3.4 ± 0.4mm; fundus: 1.4 ± 0.2mm; body: 1.4 ± 0.1mm; pylorus: 2.9 ± 0.5mm), small intestines (duodenum: 1.4 ± 0.1mm; jejunum: 1.2 ± 0.1mm; ileum: 1.4 ± 0.1mm), and large intestines (cecum: 1.2 ± 0.1mm; colon ascending: 1.4 ± 0.3 mm and descending: 1.3 ± 0.3mm). When distended the stomach did not extend beyond the caudal limits of the L2 vertebra. The cecum occupied the ventral abdominal region from T12/T13 to L7/S1, the sacculus rotundus was identified in 11 of the 23 rabbits. The sacculus rotundus and vermiform cecal appendix were identified only in rabbits with mild large intestinal distension.Conclusions and clinical relevanceIt was possible to use CT to evaluate the different portions of the GI tract that are not normally readily visible on radiographs and ultrasound (US). Normal wall thickness values of the different portion of the GI tract were stablished. These results provide new and important reference values for CT studies in normal pet rabbits and provide data for further studies in rabbits with GI diseases.     

Effects of colostrum feeding and dexamethasone treatment on mRNA levels of insulin-like growth factors (IGF)-I and -II, IGF binding proteins-2 and -3, and on receptors for growth hormone, IGF-I, IGF-II, and insulin in the gastrointestinal tract of neonatal calves

The somatotropic axis regulates growth of the gastrointestinal tract (GIT). In addition, colostrum feeding and glucocorticoids affect maturation of the GIT around birth in mammals. We have measured mRNA levels of members of the somatotropic axis to test the hypothesis that colostrum intake and dexamethasone treatment affect respective gene expression in the GIT. Calves were fed either colostrum or an isoenergetic milk-based formula, and in each feeding group, half of the calves were treated with dexamethasone (DEXA; 30 microg/kg body weight per day). Individual parameters of the somatotropic axis differed (P < 0.05) among different GIT sections and formula feeding increased (P < 0.05) mRNA levels of individual parameters at various sites of the GIT. Effects of DEXA on the somatotropic axis in the GIT partly depended on different feeding. In colostrum-fed calves, DEXA decreased (P < 0.05) mRNA levels of IGF-I (esophagus, fundus, duodenum, and ileum), IGF-II (fundus), IGFBP-2 (fundus), IGFBP-3 (fundus), IGF1R (esophagus, ileum, and colon), IGF2R (fundus), GHR (fundus), and InsR (esophagus, fundus), but in formula-fed calves DEXA increased mRNA levels of IGF-I (esophagus, rumen, jejunum, and colon). Furthermore, DEXA increased (P < 0.05) mRNA levels of IGF-II (pylorus), IGFBP-3 (duodenum), IGF2R (pylorus), and GHR (ileum), but decreased mRNA levels of IGFBP-2 (ileum), and IGF1R (fundus). Whereas formula feeding had stimulating effects, effects of DEXA treatment on the gene expression of parameters of the somatotropic axis varied among GIT sites and partly depended on feeding.     

Immunohistochemical study of endocrine cells in the gastrointestinal tract of the barking deer, Muntiacus muntjak

The morphology, distribution and relative frequencies of endocrine cells in the gastrointestinal tract of the barking deer (Muntiacus muntjak) were investigated. The immunohistochemical method employed used seven types of antisera against chromogranin, serotonin, gastrin, cholecystokinin, somatostatin, glucagon and insulin. Chromogranin and serotonin immunoreactive (IR) cells were found throughout the gastrointestinal tract. Conversely, gastrin-IR cells were only found in the oxyntic gland, pyloric gland and duodenum, while cholecystokinin-IR and somatostatin-IR cells were detected in the oxyntic gland, pyloric gland and small intestines. Somatostatin-IR cells were also seen in the caecum. Glucagon-IR cells were found in all parts of the gastrointestinal tract apart from the colon and rectum. No insulin-IR cells were found in the gastrointestinal tract of this species. The cells in the small intestine were generally spindle shaped with long cytoplasmic processes ending in the lumen (open type), while in the stomach and large intestine, they were occasionally round or spherical in shape (closed type). An uncommon distribution pattern of endocrine cells in the gastrointestinal tract of the barking deer was noted for cholecystokinin- and glucagon-IR cells.     

EVALUATION OF THE GASTROINTESTINAL TRACT IN DOGS USING COMPUTED TOMOGRAPHY

Abdominal computed tomography (CT) studies of 19 dogs with no history or clinical signs of gastrointestinal disease, and two dogs with a histological diagnosis of gastrointestinal neoplasia were examined retrospectively. Gastrointestinal segments were evaluated subjectively for conspicuity, contrast enhancement, and wall layering after contrast medium administration. In dogs without gastrointestinal disease, there were 62.8% of gastrointestinal segments (serosa to serosa) and 77.7% of gastrointestinal walls (serosa to mucosa) visualized. Wall layering on postcontrast images was seen in 21.8% of gastrointestinal segments. There was significant association between gastrointestinal diameter and wall thickness. There was significant association between weight and gastrointestinal wall thickness in the following regions: gastric fundus, gastric body, gastric pylorus, gastric pyloric antrum, duodenal cranial flexure, jejunum and ascending colon, and between patient weight and gastrointestinal diameter in cranial duodenal flexure, descending duodenum, transverse duodenum, ascending duodenum, and jejunum. Measurements acquired from CT studies correlated well with previously published normal reference ranges for radiographic and ultrasonographic studies. Gastrointestinal neoplasia, diagnosed in two dogs, had a gastrointestinal wall thickness greater than the range of the dogs without gastrointestinal disease. Computed tomography offers identification of the gastrointestinal tract segments in dogs, allows for evaluation of gastrointestinal diameter and aids in investigation of gastrointestinal wall thickness.     

GHSR—1a在奶山羊胃肠道的分布与表达

试验采用免疫组织化学、Real—timePCR和Western blotting方法测定ghrelin的功能性受体GHSR-1a（Growth hormone seeretagogue receptor-1a,GHSR-1a）在奶山羊胃肠道的分布和表达。免疫组织化学结果显示,GHSR—1a免疫阳性细胞广泛分布于奶山羊胃肠道。在皱胃主要定位于黏膜层和肌层;瘤胃、网胃和瓣胃黏膜层及肌层中也可见GHSR-1a免疫阳性细胞;在小肠主要位于十二指肠、空肠和回肠的黏膜层、黏膜下层和肌层;在结肠、盲肠和直肠GHSR—1a免疫阳性细胞也有广泛分布;GHSR—1a主要表达于内在神经丛神经细胞、胃底腺上皮细胞、肠腺上皮细胞、复层鳞状上皮细胞、平滑肌细胞中。real—timePCR和Westernblotting结果显示,皱胃、十二指肠、空肠、回肠、盲肠、结肠和直肠GHSR—1a的表达水平相对较高,显著高于瘤胃、网胃和瓣胃的表达（P〈0．05）。结果表明,ghrelin可能通过GHsR-1a对奶山羊胃肠功能具有重要的调节作用。     

Ultrasonographic measurement of gastrointestinal wall thickness and the ultrasonographic appearance of the ileocolic region in healthy cats

Ultrasound evaluation was performed on 11 healthy cats to determine wall thickness measurements for the stomach, duodenum, jejunum, ileum, and colon and to characterize the appearance of the ileocolic region. The terminal ileum had a characteristic "wagon wheel" appearance on cross-sectional images. Gastrointestinal wall thickness measurements were as follows: gastric fundus (mean, 2.0 mm; 95% confidence interval [CI], 1.7 to 2.2 mm), pylorus (mean, 2.1 mm; 95% CI, 1.9 to 2.4 mm), duodenum (mean, 2.2 mm; 95% CI, 2.0 to 2.4 mm), jejunum (mean, 2.3 mm; 95% CI, 2.1 to 2.5 mm), ileum (mean, 2.8 mm; 95% CI, 2.5 to 3.2 mm), and colon (mean, 1.5 mm; 95% CI, 1.4 to 1.7 mm).     

Immunolocalisation of serotonin, gastrin, somatostatin and glucagon in entero-endocrine cells of the goose (Anser anser)

The processes of digestion in the avian gastrointestinal tract depend on sophisticated control systems that co-ordinate secretion of digestive juices and movement of the luminal contents. In the current study, the distribution of serotonin-, gastrin-, glucagon- and somatostatin-immunoreactive endocrine cells was investigated by immunocytochemical methods in the intestinal tract of the goose. The number of cells immunoreactive for each antiserum was evaluated in different regions of the intestinal tract. Serotonin-, glucagon- and somatostatin-immunoreactive endocrine cells were seen throughout the intestinal tract, but somatostatin-immunoreactive cells were not detected in the colon of the goose. Gastrin-immunoreactive cells were detected only in the duodenum, jejunum and colon mucosa. It is concluded that the distribution pattern of the entero-endocrine cells in the goose is similar to that of most of the mammalian and other poultry species.     

Penetration in vitro of newly excysted juvenile flukes of Japanese Fasciola sp. through ligated intestines of rabbits, mice, rats and chickens.

Ligated intestines of rabbits, mice, rats and chickens were used to examine the penetration of newly excysted juvenile flukes of Japanese Fasciola sp. in vitro. In rabbit intestines, the penetration rate was relatively high in the rectum and duodenum. Penetration rates in the jejunum, ileum, cecum and colon were comparable to those in the rectum and duodenum, although it was lower in the appendix. In the case of mouse, juvenile flukes penetrated the duodenum, jejunum, cecum, and rectum at considerably high rates. In rat intestine, penetration by flukes was less in the duodenum and rectum, although flukes were detected in the jejunum. In chicken intestine, flukes barely penetrated the duodenum, jejunum and rectum. Consequently, newly excysted flukes of Fasciola sp. seem to penetrate any region of the intestine in rabbits and mice. In rats, the middle small intestine may be the site suitable for flukes to penetrate. In chickens, the difficulty in penetration of the intestinal wall may be one of the reasons why chickens are scarcely infected with Fasciola sp.     

Histologic and immunocytochemical study of endocrine cells in the gastrointestinal tract of the cow and calf

The regional distribution and relative frequency of argyrophil cells, and of cells immunoreactive for 5-hydroxytryptamine (5-HT), substance P (SP), somatostatin, glicentin, glucagon, bovine pancreatic polypeptide (BPP), gastrin, leucine-enkephalin, gastric inhibitory polypeptide (GIP), cholecystokinin, secretin, motilin, and neurotensin were studied in 9 segments from the gastrointestinal tract of cows (greater than 1 year old) and calves (less than 3 months old). Argyrophil cells, 5-HT-immunoreactive cells, and somatostatin-immunoreactive cells were distributed throughout the gastrointestinal tract, whereas the other immunoreactive cells were more restricted in distribution. Most endocrine cells were more numerous in the calf than in the cow. This feature was most conspicuous in the abomasum. In the abomasum, argyrophil cells in the cow and calf and 5-HT-immunoreactive cells in the calf were found predominantly in the fundic region, whereas somatostatin-immunoreactive cells and gastrin-immunoreactive cells in the cow and calf and 5-HT-immunoreactive cells in the cow were most numerous in the pyloric region. Substance P-, glucagon-, BPP-, and leucine-enkephalin-immunoreactive cells were rarely detected. In the small intestine, argyrophil cells, 5-HT-, SP-, somatostatin-, gastrin-, GIP-, cholecystokinin-, secretin-, and motilin-immunoreactive cells were most numerous in the duodenum. Neurotensin-, glicentin-, glucagon-, and BPP-immunoreactive cells were detected with the highest frequency in the ileum. In the large intestine, argyrophil cells and 5-HT-, glicentin-, BPP-, somatostatin-, glucagon-, and SP-immunoreactive cells occurred with the highest frequency in the rectum.     

The small intestine of the adult New Hampshire chicken: an immunohistochemical study

The presence and distribution of glucose-dependent insulinotropic polypeptide or gastric inhibitory polypeptide (GIP), gastric-releasing peptide (GRP) and glucagon immunoreactivity were studied in the small intestine of the New Hampshire chicken using immunohistochemistry. This is the first report of the presence of GIP-immunoreactive (ir) cells in avian small intestine. GIP, GRP and glucagon immunoreactivity was localized in the epithelium of the villi and crypts of the duodenum, jejunum and ileum. In particular, both in the duodenum and in the jejunum immunoreactive endocrine cells to GIP, GRP and glucagon were observed. In the ileum, we noticed GIP-ir and glucagon-ir cells. GRP-ir was found in nerve fibres of all three segments of the small intestine. The distribution of these bioactive agents in the intestinal tract of the chicken suggests that GIP and glucagon may play a role in the enteropancreatic axis in which intestinal peptides modulate pancreas secretion.