scholarly journals Localization of amidating enzymes (PAM) in rat gastrointestinal tract.

1993 ◽  
Vol 41 (11) ◽  
pp. 1617-1622 ◽  
Author(s):  
A Martínez ◽  
M A Burrell ◽  
M Kuijk ◽  
L M Montuenga ◽  
A Treston ◽  
...  
Keyword(s):  
Small Intestine ◽  
In Situ Hybridization ◽  
Gastrointestinal Tract ◽  
Digestive Tract ◽  
Endocrine Cells ◽  
Regulatory Peptides ◽  
Serial Sections ◽  
Gastric Glands ◽  
Amidating Enzymes

We studied the distribution of the two enzymes involved in post-translational C-terminal alpha-amidation of regulatory peptides in rat digestive tract, using immunocytochemical methods and in situ hybridization techniques. The enzymes were located in most of the fibers and neurons of the myenteric and submucous plexus throughout the entire digestive tract and in endocrine cells of the stomach and colon. Staining of reverse-face serial sections demonstrated that the enzymes in endocrine cells of the stomach co-localized with gastrin in the bottom of the gastric glands. Some gastrin-immunoreactive cells near the neck of the gland were negative for PAM, suggesting that amidation takes place only in the more mature cells. In the colon all cells immunoreactive for glucagon and GLP1 were also positive for peptidylglycine alpha-hydroxylating monooxygenase (PHM) but not for peptidyl-alpha-hydroxyglycine alpha-amidating lyase (PAL). The absence of immunoreactivity for the amidating enzymes in endocrine cells of the small intestine, known to produce C-terminally amidated peptides, suggests the existence of other amidating enzymes.

scholarly journals Differential Cellular Expression of Galectin Family mRNAs in the Epithelial Cells of the Mouse Digestive Tract

2005 ◽  
Vol 53 (11) ◽  
pp. 1323-1334 ◽  
Author(s):  
Junko Nio ◽  
Yasuhiro Kon ◽  
Toshihiko Iwanaga
Keyword(s):  
Small Intestine ◽  
Digestive Tract ◽  
Large Intestine ◽  
Mucous Cells ◽  
Cell Stage ◽  
Gastric Glands ◽  
Specific Expression ◽  
Cellular Expression ◽  
Galectin 3

Galectin is an animal lectin that recognizes β-galactosides of glycoconjugates and is abundant in the gut. This study revealed the cellular expression of galectin subtypes throughout the mouse digestive tract by in situ hybridization. Signals for five subtypes (galectin-2, -3, -4/6, and -7) were detected exclusively in the epithelia. In the glandular stomach, galectin-2 and -4/6 were predominantly expressed from gastric pits to neck of gastric glands, where mucous cells were the main cellular sources. The small intestine exhibited intense, maturation-associated expressions of galectin-2, -3, and -4/6 mRNAs. Galectin-2 was intensely expressed from crypts to the base of villi, whereas transcripts of galectin-3 gathered at villous tips. Signals for galectin-4/6 were most intense at the lower half of villi. Galectin-2 was also expressed in goblet cells of the small intestine but not in those of the large intestine. In the large intestine, galectin-4/6 predominated, and the upper half of crypts simultaneously contained transcripts of galectin-3. Stratified epithelium from the lip to forestomach and anus intensely expressed galectin-7 with weak expressions of galectin-3. Because galectins in the digestive tract may be multi-functional, information on their cell/stage-specific expression contributes to a better understanding of the functions and pathological involvements of galectins.

Expression and localization of aquaporins in rat gastrointestinal tract

1999 ◽  
Vol 276 (3) ◽  
pp. C621-C627 ◽  
Author(s):  
Yu Koyama ◽  
Tadashi Yamamoto ◽  
Tatsuo Tani ◽  
Kouei Nihei ◽  
Daisuke Kondo ◽  
...  
Keyword(s):  
Small Intestine ◽  
In Situ Hybridization ◽  
Gastrointestinal Tract ◽  
Epithelial Cells ◽  
Cellular Localization ◽  
Basolateral Membrane ◽  
Rnase Protection Assay ◽  
Rnase Protection ◽  
Basolateral Membranes

A family of water-selective channels, aquaporins (AQP), has been demonstrated in various organs and tissues. However, the localization and expression of the AQP family members in the gastrointestinal tract have not been entirely elucidated. This study aimed to demonstrate the expression and distribution of several types of the AQP family and to speculate on their role in water transport in the rat gastrointestinal tract. By RNase protection assay, expression of AQP1–5 and AQP8 was examined in various portions through the gastrointestinal tract. AQP1 and AQP3 mRNAs were diffusely expressed from esophagus to colon, and their expression was relatively intense in the small intestine and colon. In contrast, AQP4 mRNA was selectively expressed in the stomach and small intestine and AQP8 mRNA in the jejunum and colon. Immunohistochemistry and in situ hybridization demonstrated cellular localization of these AQP in these portions. AQP1 was localized on endothelial cells of lymphatic vessels in the submucosa and lamina propria throughout the gastrointestinal tract. AQP3 was detected on the circumferential plasma membranes of stratified squamous epithelial cells in the esophagus and basolateral membranes of cardiac gland epithelia in the lower stomach and of surface columnar epithelia in the colon. However, AQP3 was not apparently detected in the small intestine. AQP4 was present on the basolateral membrane of the parietal cells in the lower stomach and selectively in the basolateral membranes of deep intestinal gland cells in the small intestine. AQP8 mRNA expression was demonstrated in the absorptive columnar epithelial cells of the jejunum and colon by in situ hybridization. These findings may indicate that water crosses the epithelial layer through these water channels, suggesting a possible role of the transcellular route for water intake or outlet in the gastrointestinal tract.

The distribution of endocrine cell progenitors in the gut of chick embryos

Development ◽  
1984 ◽  
Vol 82 (1) ◽  
pp. 131-145
Author(s):  
B. B. Rawdon ◽  
Beverley Kramer ◽  
Ann Andrew
Keyword(s):  
Gastrointestinal Tract ◽  
Progenitor Cells ◽  
Digestive Tract ◽  
Pancreatic Polypeptide ◽  
Endocrine Cell ◽  
Endocrine Cells ◽  
Chick Embryos ◽  
Intact Embryo ◽  
Pancreatic Endocrine Cells ◽  
Gut Endocrine Cells

The aim of this experiment was to find out whether or not, at early stages of development, progenitors of the various types of gut endocrine cells are localized to one or more specific regions of the gastrointestinal tract. Transverse strips of blastoderm two to four somites in length were excised between the levels of somites 5 and 27 in chick embryos at 5- to 24-somite stages and were cultured as chorioallantoic grafts. The distribution of endocrine cells in the grafts revealed confined localization of progenitor cells only in the case of insulinimmunoreactive cells. Theprogenitors of cells with somatostatin-, pancreatic polypeptide-, glucagon-, secretin-, gastrin/CCK-, motilin-, neurotensin- and serotonin-like immunoreactivity were distributed along the length of the presumptive gut at the time of explantation; indeed, in many cases they were more widespread than are their differentiated progeny in normal gut of the same age. This finding indicates that conditions in grafts must differ from those that operate in the intact embryo. Also it may explain the occurrence of ectopic gut or pancreatic endocrine cells in tumours of the digestive tract.

GASTROINTESTINAL HYPOMOTILITY IN MAGNESIUM-DEFICIENT SHEEP

1980 ◽  
Vol 60 (2) ◽  
pp. 293-301 ◽  
Author(s):  
L. BUENO ◽  
J. FIORAMONTI ◽  
E. GEUX ◽  
Y. RAISSIGUIER
Keyword(s):  
Small Intestine ◽  
Gastrointestinal Tract ◽  
Electrical Activity ◽  
Digestive Tract ◽  
Experimental Period ◽  
Proximal Colon ◽  
Slow Waves ◽  
Deficient Diet ◽  
Intravenous Infusions ◽  
Spiking Activity

The electrical activity of the gastrointestinal tract and gallbladder was recorded in four sheep fed a Mg-deficient diet during 10 to 15 days. The mitigating effect of intravenous infusions of MgCl2 was tested at the end of the experimental period in animals presenting hypomagnesemia. Motility of the reticulo-rumen remained unchanged in Mg-deficient sheep except that there was no postprandial increased frequency of contractions. By contrast, the contractions of gallbladder, cecum and proximal colon were reduced in both amplitude and frequency. The amplitude but not the frequency of the antro-duodenal slow-waves was reduced. The amplitude of the regular spiking activity of the small intestine was reduced as well as the number of complexes produced per day. The activity of the spiral colon was correlated to the blood magnesium concentrations but Mg infusion was unable to restore immediately the motor profile of the rest of the gut to its intitial level. This was done within 2–3 days by changes in the diet in three of the four animals. It is concluded that the motility of the whole digestive tract, including the reticulo-rumen, is modified on a Mg-deficient diet and that hypomagnesemia, involved in the atony of the spiral colon, is only one of the factors responsible for the hypomotility.

Location of PHM/VIP mRNA in human gastrointestinal tract detected by in situ hybridization

1994 ◽  
Vol 276 (2) ◽  
pp. 229-238 ◽  
Author(s):  
Helle E. Bredkj'r ◽  
Birgitte S. Wulff ◽  
Piers C. Emson ◽  
Jan Fahrenkrug
Keyword(s):  
In Situ Hybridization ◽  
Gastrointestinal Tract ◽  
Human Gastrointestinal Tract

Location of PHM/VIP mRNA in human gastrointestinal tract detected by in situ hybridization

1994 ◽  
Vol 276 (2) ◽  
pp. 229-238 ◽  
Author(s):  
Helle E. Bredkj�r ◽  
Birgitte S. Wulff ◽  
Piers C. Emson ◽  
Jan Fahrenkrug
Keyword(s):  
In Situ Hybridization ◽  
Gastrointestinal Tract ◽  
Human Gastrointestinal Tract

Interaction between sites of magnesium absorption in the digestive tract of the sheep

1976 ◽  
Vol 27 (3) ◽  
pp. 437 ◽  
Author(s):  
FM Tomas ◽  
BJ Potter
Keyword(s):  
Small Intestine ◽  
Gastrointestinal Tract ◽  
Digestive Tract ◽  
Magnesium Chloride ◽  
Basal Diet ◽  
Faecal Excretion ◽  
Intestinal Segments ◽  
Effect Of Treatment ◽  
The Mean ◽  
Plasma Magnesium

The effect of magnesium chloride infusion to different sites in the gastrointestinal tract of sheep upon the net absorption of magnesium from different regions of the digestive tract has been examined. Four Merino wethers were each prepared with cannulas sited in the rumen, in the duodenum adjacent to the pylorus and in the terminal ileum. The basal diet provided 18.45 mmoles magnesium/ day and an additional 65 mmoles magnesium/day as magnesium chloride was continuously infused into (A) the rumen, (B) the rumen and duodenum in equal portions, (C) the duodenum and (D) the terminal ileuni. A continuous infusion of Cr-EDTA to the ruinen enabled digcsta and magnesium flow rates to be estimated from digesta samples obtained from the intestinal cannulas at 4 hr intervals over 3 days. For treatments A, B, C and D respectively, the mean net absorption of magnesium (mmoles/day) from the rumen was 20.4, 11.4, 1.4 and 3.4; from the small intestine –0.5, 1.7, –5.1 and –9.8; from the large intestine 4.6, 2.2, 12.7 and 12.3; and from the total gastrointestinal tract 24.6, 15.4, 9.1 and 4.9. In each case the effect of treatment was significant. The total net absorption of magnesium caudal to the pylorus was unaffected by treatment. Plasma magnesium levels were reduced during post-ruminal infusion of magnesium, but these changes were not obviously linked to the changed net absorption from the intestinal segments. The urinary and faecal excretion of magnesium, but not the magnesium balance, was strongly related to the total net absorption of magnesium. The results emphasize the major contribution of the stomach to the gastrointestinal net absorption of magnesium and show that although the amount absorbed from this region may influence separately the net absorption from the large and small intestine, it does not appear to influence the overall intestinal net absorption of magnesium.

Sign in / Sign up

Export Citation Format

Share Document