scholarly journals Intestinal Monoacylglycerol Metabolism

2007 ◽  
Vol 282 (46) ◽  
pp. 33346-33357 ◽  
Author(s):  
Su-Hyoun Chon ◽  
Yin Xiu Zhou ◽  
Joseph L. Dixon ◽  
Judith Storch

Intestinal monoacylglycerol (MG) metabolism is well known to involve its anabolic reesterification to triacylglycerol (TG). We recently provided evidence for enterocyte MG hydrolysis and demonstrated expression of the monoacylglycerol lipase (MGL) gene in human intestinal Caco-2 cells and rodent small intestinal mucosa. Despite the large quantities of MG derived from dietary TG, the regulation of MG metabolism in the intestine has not been previously explored. In the present studies, we examined the mRNA expression, protein expression, and activities of the two known MG-metabolizing enzymes, MGL and MGAT2, in C57BL/6 mouse small intestine, as well as liver and adipose tissues, during development and under nutritional modifications. Results demonstrate that MG metabolism undergoes tissue-specific changes during development. Marked induction of small intestinal MGAT2 protein expression and activity were found during suckling. Moreover, while substantial levels of MGL protein and activity were detected in adult intestine, its regulation during ontogeny was complex, suggesting post-transcriptional regulation of expression. In addition, during the suckling period MG hydrolytic activity is likely to derive from carboxyl ester lipase rather than MGL. In contrast to intestinal MGL, liver MGL mRNA, protein and activity all increased 5–10-fold during development, suggesting that transcriptional regulation is the primary mechanism for hepatic MGL expression. Three weeks of high fat feeding (40% kcal) significantly induced MGL expression and activity in small intestine relative to low fat feeding (10% kcal), but little change was observed upon starvation, suggesting a role for MGL in dietary lipid assimilation following a high fat intake.

Cells ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 3168
Author(s):  
Takashi Nakanishi ◽  
Hirokazu Fukui ◽  
Xuan Wang ◽  
Shin Nishiumi ◽  
Haruka Yokota ◽  
...  

Although high-fat diet (HFD)-related dysbiosis is involved in the development of steatohepatitis, its pathophysiology especially in the small intestine remains unclear. We comprehensively investigated not only the liver pathology but also the microbiome profile, mucosal integrity and luminal environment in the small intestine of mice with HFD-induced obesity. C57BL/6J mice were fed either a normal diet or an HFD, and their small-intestinal contents were subjected to microbial 16S rDNA analysis. Intestinal mucosal permeability was evaluated by FITC-dextran assay. The levels of bile acids in the small-intestinal contents were measured by liquid chromatography/mass spectrometry. The expression of tight junction molecules, antimicrobial peptides, lipopolysaccharide and macrophage marker F4/80 in the small intestine and/or liver was examined by real-time RT-PCR and immunohistochemistry. The abundance of Lactobacillus was markedly increased and that of Clostridium was drastically decreased in the small intestine of mice fed the HFD. The level of conjugated taurocholic acid was significantly increased and those of deconjugated cholic acid/secondary bile acids were conversely decreased in the small-intestinal contents. The expression of occludin, antimicrobial Reg IIIβ/γ and IL-22 was significantly decreased in the small intestine of HFD-fed mice, and the intestinal permeability was significantly accelerated. Infiltration of lipopolysaccharide was significantly increased in not only the small-intestinal mucosa but also the liver of HFD-fed mice, and fat drops were apparently accumulated in the liver. Pathophysiological alteration of the luminal environment in the small intestine resulting from a HFD is closely associated with minimal inflammation involving the gut-liver axis through disturbance of small-intestinal mucosal integrity.


2001 ◽  
Vol 280 (6) ◽  
pp. G1187-G1196 ◽  
Author(s):  
James T. Mahan ◽  
Ghanshyam D. Heda ◽  
R. Hanumantha Rao ◽  
Charles M. Mansbach

We identified the enzyme responsible for alkaline lipolysis in mucosa of rat small intestine. RT-PCR was used to amplify a transcript that, by cloning and sequencing, is identical to pancreatic triacylglycerol lipase. In rats fed normal laboratory chow, pancreatic triacylglycerol lipase mRNA was detected in all four quarters of the small intestine, with the first quarter expressing about three times as much of this transcript as was found in the more distal three-quarters combined. Both acutely and chronically administered dietary fat were shown to regulate pancreatic triacylglycerol lipase mRNA expression and lipase activity. The synthesis of pancreatic triacylglycerol lipase protein by the small intestine was demonstrated by in vivo radiolabeling experiments using [35S]methionine/cysteine followed by immunoprecipitation with an anti-pancreatic triacylglycerol lipase antibody. Immunohistochemical studies suggest that pancreatic triacylglycerol lipase protein expression is restricted to enterocytes throughout the small intestine. To our knowledge, this is the first report identifying rat small intestinal mucosa as a site of pancreatic triacylglycerol lipase synthesis and the first demonstration of its modulation in the mucosa by dietary fat. We propose that pancreatic triacylglycerol lipase is used by the intestine to hydrolyze the mucosal triacylglycerol that is not transported in chylomicrons.


1985 ◽  
Vol 104 (2) ◽  
pp. 435-443 ◽  
Author(s):  
A. N. Janes ◽  
T. E. C. Weekes ◽  
D. G. Armstrong

SummaryTwo groups of six sheep were fed either dried-grass or ground maize-based diets for at least 4 weeks before slaughter. Samples of the small intestinal mucosa and spancreatic tissue were assayed for a-amylase, glucoamylase, maltase and oligo-l,6-glucosidase.The pancreatic tissue contained high activities of α-amylase and much lower activities of glucoamylase, maltase and oligo-1,6-glucosidase. There was no effect of diet on the specific activities of any of these enzymes in the pancreatic tissue.The activity of α-amylase adsorbed on to the mucosa of the small intestine was greatest in the proximal region of the small intestine, the activity generally declining with increasing distance away from the pylorus. There was no diet effect on the absorbed α-amylase activity.Similar patterns of distribution along the small intestine were observed for maltase, glucoamylase and oligo-1,6-glucosidase with the highest activities in t he jejunum. There was no overall effect of diet on glucoamylase or maltase specific activities and glucoamylase total activity, although the total activities of maltase and oligo-1,6-glucosidase were significantly greater for the sheep fed the ground maize-based diet (P < 0·05).It is suggested that ruminant animals may be capable of digesting large amounts of starch in the small intestine through an adaptation in the activity of the host carbohydrases.


2015 ◽  
Vol 139 (6) ◽  
pp. 791-795 ◽  
Author(s):  
Stephen Lagana ◽  
Susan Hsiao ◽  
Fei Bao ◽  
Antonia Sepulveda ◽  
Roger Moreira ◽  
...  

Context HepPar-1 and Arginase-1 are urea cycle enzymes used to distinguish hepatocellular carcinoma from other carcinomas. HepPar-1, but not Arginase-1, is known to be immunoreactive with normal human small intestine. Objectives To better define and compare the immunohistochemical staining patterns of HepPar-1 and Arginase-1 in adenocarcinomas arising in the small intestine, including the ampullary region. Design Staining for HepPar-1 and Arginase-1 was performed on 20 nonampullary small intestinal adenocarcinomas and 32 adenocarcinomas from the ampullary region. Ampullary adenocarcinomas were divided into intestinal morphology (15), pancreatobiliary morphology (14), and unclassifiable (3). Nonneoplastic small intestinal mucosa and colorectal adenocarcinomas were used as control groups. Results HepPar-1 stained 12 of 20 nonampullary small intestinal adenocarcinomas, with a median of 63% of cells staining in positive cases. It also stained 11 of 15 ampullary carcinomas with intestinal morphology, with a median of 75% of cells staining in positive cases. Two of 14 ampullary carcinomas with pancreatobiliary morphology were positive for HepPar-1. Arginase-1 showed positivity in 2 ampullary region carcinomas and diffuse positivity in 1 duodenal adenocarcinoma. Two of 22 colorectal carcinomas stained for HepPar-1 with none positive for Arginase-1. Conclusions HepPar-1, but not Arginase-1, usually shows positivity in small intestinal adenocarcinomas and ampullary adenocarcinomas with intestinal morphology, but only rarely shows positivity in ampullary adenocarcinomas with pancreatobiliary morphology. HepPar-1 positivity in metastatic adenocarcinoma with intestinal morphology is suggestive of an upper gastrointestinal primary site.


2011 ◽  
Vol 300 (1) ◽  
pp. E188-E194 ◽  
Author(s):  
Juan C. Marini ◽  
Bettina Keller ◽  
Inka Cajo Didelija ◽  
Leticia Castillo ◽  
Brendan Lee

The synthesis of citrulline from arginine in the small intestine depends on the provision of ornithine. To test the hypothesis that arginase II plays a central role in the supply of ornithine for citrulline synthesis, the contribution of dietary arginine, glutamine, and proline was determined by utilizing multitracer stable isotope protocols in arginase II knockout (AII−/−) and wild-type (WT) mice. The lack of arginase II resulted in a lower citrulline rate of appearance (121 vs. 137 μmol·kg−1·h−1) due to a reduced availability of ornithine; ornithine supplementation was able to restore the rate of citrulline production in AII−/− to levels comparable with WT mice. There were significant differences in the utilization of dietary citrulline precursors. The contribution of dietary arginine to the synthesis of citrulline was reduced from 45 to 10 μmol·kg−1·h−1 due to the lack of arginase II. No enteral utilization of arginine was observed in AII−/− mice (WT = 25 μmol·kg−1·h−1), and the contribution of dietary arginine through plasma ornithine was reduced in the transgenic mice (20 vs. 13 μmol·kg−1·h−1). Dietary glutamine and proline utilization were greater in AII−/− than in WT mice (20 vs. 13 and 1.4 vs. 3.7 μmol·kg−1·h−1, respectively). Most of the contribution of glutamine and proline was enteral rather than through plasma ornithine. The arginase isoform present in the small intestinal mucosa has the role of providing ornithine for citrulline synthesis. The lack of arginase II results in a greater contribution of plasma ornithine and dietary glutamine and proline to the synthesis of citrulline.


2008 ◽  
Vol 53 (No. 10) ◽  
pp. 525-532 ◽  
Author(s):  
R. Zitnan ◽  
J. Voigt ◽  
S. Kuhla ◽  
J. Wegner ◽  
A. Chudy ◽  
...  

The objective of this study was to investigate rumen fermentation, apparent digestibility of nutrients, and morphology of ruminal und intestinal mucosa in two cattle breeds of different metabolic type. From each breed six purebred German Holstein (H) bulls representing the secretion type and six Charolais (CH) bulls representing the accretion type were raised and fattened under identical conditions with <I>semi ad libitum</I> feeding of a high energy diet. The animals were used for a digestion trial started at nine months of age and animals were slaughtered at 18 months of age. Body weight (668 vs. 764 kg, <I>P</I> = 0.011), body weight gain (1 223 vs. 1 385 g/day, <I>P</I> = 0.043), and body protein gain (93 vs. 128 g/day, <I>P</I> = 0.001) were lower in H compared to CH bulls. Protein expense per kg protein accretion was higher in H bulls (13.8 vs. 10.2, <I>P</I> = 0.001). No significant differences were found in concentration and pattern of ruminal short chain fatty acid and in apparent digestibility of organic matter, crude fibre, and N-free extracts. There were no significant differencs in all morphometric traits of rumen mucosa between both cattle breeds. Compared to H, the villi of CH bulls were higher in duodenum (586 vs. 495 &mu;m, <I>P</I> = 0.001) and proximal jejunum (598 vs. 518&mu;m, <I>P</I> < 0.001), the crypt were deeper in duodenum (295 vs. 358, <I>P</I>< 0.001) and proximal jejunum (292 vs. 344 &mu;m, <I>P</I> = 0.020). In contrast, the villi in ileum were higher in H (522 vs. 471 &mu;m, <I>P</I> = 0.006). The weight of total small intestine, as percentage of total body weight, was 1.1 in H and 0.8 in CH (<I>P</I> = 0.002). The utilization of food crude protein was positively related to the duodenal (<I>P</I> = 0.001) and proximal jejunal villus height (<I>P</I> = 0.003) and to the duodenal crypt depth (<I>P</I> < 0.001) and negatively related to weight of small intestine (<I>P</I> = 0.004). It is concluded, that the higher growth potential and feed efficiency in CH bulls compared to H bulls is not caused by differences in digestion processes, but in size of small intestine, and morphology of small intestinal mucosa. Obviously the duodenum and proximal jejunum of CH bulls adapt to increase the absorptive surface due to the increase in nutrient demand.


1995 ◽  
Vol 42 (3) ◽  
pp. 297-299
Author(s):  
L P Arciuch ◽  
A Omasta ◽  
K Rostkowska ◽  
M Gałazyn-Sidorczuk ◽  
J Moniuszko-Jakoniuk ◽  
...  

Inhibition by ethanol of the activities of lysosomal exoglycosidases in stomach, small intestine, liver and brain of rats exposed to cadmium (Cd2+) was determined. Out of the glycosidases tested the most distinct effect of Cd2+ and ethanol administered to the rats in vivo was observed in the small intestinal mucosa in a decreasing order: N-acetyl-beta-hexosaminidase, beta-galactosidase and alpha-fucosidase.


2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Zhongshen Kuang ◽  
Tingting Jin ◽  
ChangYi Wu ◽  
Yanan Zong ◽  
Panpan Yin ◽  
...  

This study is aimed at exploring the effects of lentinan on small intestinal mucosa as well as lung and liver injury in mice with gut-origin sepsis. Cecal ligation and perforation (CLP) were used to construct a mouse model of gut-origin sepsis. The mice were randomly divided into six groups: sham operation group (sham), gut-origin sepsis model group (CLP), ulinastatin-positive drug control group (UTI), lentinan low concentration group (LTN-L, 5 mg/kg), lentinan medium concentration group (LTN-M, 10 mg/kg), and lentinan high concentration group (LTN-H, 20 mg/kg). H&E staining was used to detect the pathological damage of the small intestine, liver, and lung. The serum of mice in each group was collected to detect the expression changes of inflammatory cytokines, oxidative stress biomarkers, and liver function indexes. In vitro assessment of bacterial translocation was achieved through inoculated culture media. Western blot and RT-qPCR were used to detect the expression of molecules related to the NF-κB signaling pathway in the small intestine tissues of mice. The results showed that compared with the CLP group, the injury degree of the small intestine, liver, and lung in mice with gut-origin sepsis was improved with the increase of lentinan concentration. In addition, TNF-α, IL-1β, IL-6, and HMGB1 were decreased with the increase of lentinan concentration, but the expression of IL-10 was increased. Lentinan could also reduce the expression of oxidative stress injury indexes and liver function indexes and inhibit bacterial translocation to liver and lung tissues. Further mechanism investigation revealed that lentinan downregulated the expression of the NF-κB signaling pathway molecules (NF-κB, TLR4, and Bax) and upregulated the expression of occludin and Bcl-2. In conclusion, lentinan inhibits the activity of the NF-κB signaling pathway, thus attenuating injuries of small intestinal mucosa and liver and lung in mice with gut-origin sepsis and reducing the inflammatory response in the process of sepsis.


2013 ◽  
Vol 110 (8) ◽  
pp. 1421-1428 ◽  
Author(s):  
Jonatan Miranda ◽  
María P. Portillo ◽  
Juan Antonio Madrid ◽  
Noemí Arias ◽  
M. Terasa Macarulla ◽  
...  

In mammals, the main component of the circadian system is the suprachiasmatic nucleus in the hypothalamus. However, circadian clocks are also present in most peripheral tissues, such as adipose tissue. The aim of the present study was to analyse the potential effects of resveratrol on changes induced by high-fat feeding in the expression of clock genes and clock-controlled genes in the white adipose tissue from rats. For this purpose, rats were divided into three groups: a control group, fed a standard diet, and two other groups, either fed a high-fat diet supplemented with resveratrol (RSV) or no resveratrol (HF). The expression of clock genes and clock-controlled genes was analysed by RT-PCR. Protein expression and fatty acid synthase (FAS) activity were also analysed. When comparing the controls, the RSV group showed similar patterns of response to the HF group, except for reverse erythroblastosis virus α (Rev-Erbα), which was down-regulated. The expression of this gene reached the same levels as in control rats. The response pattern of protein expression forRev-Erbαwas similar to that found for gene expression. High-fat feeding up-regulated all adipogenic genes and resveratrol did not modify them. In the HF group, the activity of FAS tended to increase, while resveratrol decreased. In conclusion, resveratrol reverses the change induced by high-fat feeding in the expression ofRev-Erbαin adipose tissue, which means that clock machinery is a target for this polyphenol. This change seems to be related to reduced lipogenesis, which might be involved in the body fat-lowering effect of this molecule.


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