Gastroenterology Category

Prostaglandins modulate gut epithelial cell proliferation and survival. Prostaglandins are synthesized from arachi-donic acid by either of two cyclo-oxygenases (COX) — COX-1 or COX-2. COX-1 is constitutively expressed, and COX-2 is inducible by cytokines and by various other stimuli. Indomethacin, an inhibitor of COX-1 and COX-2, further reduces the number of surviving crypt cells in […]

Acute radiation enteritis is a common occurrence after abdominal radiotherapy. This enteritis is associated with anorexia, nausea, diarrhea and weight loss. Following radiotherapy, the rate of small intestinal transit is increased. Following irradiation in ferrets, there is an initial increase in the frequency of the ileal pressure waves, followed by a nonsignificant reduction in the […]

The premature induction of BBM enzymes by exogenous insulin is mediated by the binding of the hormone to its intestinal receptor. Binding of insulin to the extramembra-nous domain of the intestinal receptor induces a conformational change allowing phosphorylation of the tyrosine kinase domain. This binding of insulin to its receptor is higher in the crypt […]

Patients with long standing insulin-dependent diabetes mellitus develop absorption and motility abnormalities in the intestine. The abnormal postprandial duodenal chyme transport is characterized by disturbed chyme clearance. Duodenal bicarbonate secretion is reduced in diabetic rats due to vagal-dependent neuronal dysfunction, and to decreased sensitivity of the bicarbonate secreting cell. Acute hyperglycemia inhibits gastric and pancreatic […]

Various growth factors and cytokines present in the epithelium or LP of the intestinal mucosa modulate epithelial cell migration and growth in vitro. Hepatocyte growth factor is present in high concentrations in amniotic fluid and stimulates intestinal epithelial cell migration during the development of the fetal small intestine. Gut-enriched Kruppel-like factor is a transcription factor […]

An EGFR raf-dependent mechanism is necessary for Ras but not for src transformation of intestinal epithelial cells. Polyamines (putrescine, spermidine and sperminine) are involved in DNA, RNA and protein synthesis and thus the polyamines are essential for cell proliferation and growth. Putrescine is taken up from the systemic circulation by the small bowel and is […]

The intestinal epithelium is characterized by rapid cell turnover, with pluripotent stem cells in the crypts of Lieberkuhn providing a continuous supply of cells that are directed into a variety of maturation pathways. The development and maintenance of normal intestinal morphology require regulation of the daughter cells’ proliferative status, lineage allocation, migration, differentiation and apoptosis. […]