The hexoses glucose, galactose and fructose serve as important dietary energy sources in animals and glucose plays a central role in energy homeostasis within eucaryotic cells. As relatively little is known about patt...The hexoses glucose, galactose and fructose serve as important dietary energy sources in animals and glucose plays a central role in energy homeostasis within eucaryotic cells. As relatively little is known about patterns of hexose transporters expression in birds gastrointestinal tract, the aim of the study was to examine glucose transporters 2 （GLUT-2） and glucose transporters 5 （GLUT-5） expression in stomach and duodenal epithelium of two different species--broilers （Gallus gallus domesticus） and ostriches （Struthio camelus var. domesticus） chicken. Materials from the two parts of gastrointestinal tract were collected from six 7-day-old female broilers and six 7-day-old female ostriches. Specimens were fixed with 10% formalin, embedded into paraffin, cut into 7 lain thick slices, followed by immunohistochemical staining with polyclonal primary antibodies rabbit anti-GLUT-2 and rabbit anti-GLUT-5; the staining was carried out according to the manufacturers guidelines （IHC kit, Abcam, UK）. The investigation showed that the staining for both antibodies was more intensive in the epithelial cells of stomach and duodenum of the 7-day-old broilers. In duodenal epithelium, goblet cells and brush border membranes were stained in both species, however the signal was stronger for GLUT-5 than GLUT-2. Staining for GLUT-2 and GLUT-5 occurred in different parts of gastrointestinal tract of 7-day-old ostriches, but was weaker compared to 7-day-old broilers, which showed that the gastrointestinal tract of 7-day-old female broilers was more developed for transportation ofhexoses than 7-day-old female ostriches.展开更多
Carbohydrates are an important component of the diet. The carbohydrates that we ingest range from simple monosaccharides （glucose, fructose and galactose） to disaccharides （lactose, sucrose） to complex polysacchar...Carbohydrates are an important component of the diet. The carbohydrates that we ingest range from simple monosaccharides （glucose, fructose and galactose） to disaccharides （lactose, sucrose） to complex polysaccharides. Most carbohydrates are digested by salivary and pancreatic amylases, and are further broken down into monosaccharides by enzymes in the brush border membrane （BBM） of enterocytes. For example, lactase-phloridzin hydrolase and sucraseisomaltase are two disaccharidases involved in the hydrolysis of nutritionally important disaccharides. Once monosaccharides are presented to the BBM, mature enterocytes expressing nutrient transporters transport the sugars into the enterocytes. This paper reviews the early studies that contributed to the development of a working model of intestinal sugar transport, and details the recent advances made in understanding the process by which sugars are absorbed in the intestine.展开更多
文摘The hexoses glucose, galactose and fructose serve as important dietary energy sources in animals and glucose plays a central role in energy homeostasis within eucaryotic cells. As relatively little is known about patterns of hexose transporters expression in birds gastrointestinal tract, the aim of the study was to examine glucose transporters 2 （GLUT-2） and glucose transporters 5 （GLUT-5） expression in stomach and duodenal epithelium of two different species--broilers （Gallus gallus domesticus） and ostriches （Struthio camelus var. domesticus） chicken. Materials from the two parts of gastrointestinal tract were collected from six 7-day-old female broilers and six 7-day-old female ostriches. Specimens were fixed with 10% formalin, embedded into paraffin, cut into 7 lain thick slices, followed by immunohistochemical staining with polyclonal primary antibodies rabbit anti-GLUT-2 and rabbit anti-GLUT-5; the staining was carried out according to the manufacturers guidelines （IHC kit, Abcam, UK）. The investigation showed that the staining for both antibodies was more intensive in the epithelial cells of stomach and duodenum of the 7-day-old broilers. In duodenal epithelium, goblet cells and brush border membranes were stained in both species, however the signal was stronger for GLUT-5 than GLUT-2. Staining for GLUT-2 and GLUT-5 occurred in different parts of gastrointestinal tract of 7-day-old ostriches, but was weaker compared to 7-day-old broilers, which showed that the gastrointestinal tract of 7-day-old female broilers was more developed for transportation ofhexoses than 7-day-old female ostriches.
文摘Carbohydrates are an important component of the diet. The carbohydrates that we ingest range from simple monosaccharides （glucose, fructose and galactose） to disaccharides （lactose, sucrose） to complex polysaccharides. Most carbohydrates are digested by salivary and pancreatic amylases, and are further broken down into monosaccharides by enzymes in the brush border membrane （BBM） of enterocytes. For example, lactase-phloridzin hydrolase and sucraseisomaltase are two disaccharidases involved in the hydrolysis of nutritionally important disaccharides. Once monosaccharides are presented to the BBM, mature enterocytes expressing nutrient transporters transport the sugars into the enterocytes. This paper reviews the early studies that contributed to the development of a working model of intestinal sugar transport, and details the recent advances made in understanding the process by which sugars are absorbed in the intestine.
