title: Age-related differences in receptors for Escherichia coli heat-stable enterotoxin in the small and large intestine of children.
abstract: Escherichia coli that produce heat-stable enterotoxin are a worldwide cause of diarrheal disease, especially in children. We examined small and large intestinal specimens from children of various ages for the presence of E. coli heat-stable entero-toxin receptors and determined whether the number of receptors or the binding affinity of these receptors was related to the age of the child. We observed specific binding of 125I-heat-stable enterotoxin to all small intestinal and colonic specimens. However, a greater number of receptors per microgram of membrane protein were present in infants and the number of receptors rapidly decreased with increasing age. We also observed that increased heat-stable enterotoxin stimulation of guanylate cyclase was correlated with increased receptor density. We suggest that a greater number of gastrointestinal receptors for heat-stable enterotoxin, capable of activating more guanylate cyclase, may contribute to the increased severity of diarrhea noted in young children exposed to enterotoxigenic E. coli.
mesh_terms: D000293:Adolescent; D000367:Age Factors; D001667:Binding, Competitive; D002648:Child; D002675:Child, Preschool; D003106:Colon / Q000378:metabolism; D004789:Enzyme Activation; D006162:Guanylate Cyclase / Q000378:metabolism; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007413:Intestinal Mucosa / Q000378:metabolism*; D007421:Intestine, Small / Q000378:metabolism; D007422:Intestines / Q000201:enzymology; D011956:Receptors, Cell Surface / Q000032:analysis*; D000074261:Receptors, Enterotoxin; D050705:Receptors, Guanylate Cyclase-Coupled; D018000:Receptors, Peptide
chemical_list: D011956:Receptors, Cell Surface; D018000:Receptors, Peptide; D006162:Guanylate Cyclase; D000074261:Receptors, Enterotoxin; D050705:Receptors, Guanylate Cyclase-Coupled