title: Effects of neomycin on galactose absorption across rat jejunum.
abstract: The effects of neomycin sulphate on galactose absorption have been studied using in vivo and in vitro preparations of rat small intestine. Neomycin (10(-3)M) produced an increase in the maximum transport capacity (Jmax) for the active component of absorption in vivo. The apparent Kt for absorption was unaffected. The antibiotic caused a dose-dependent increase in the potential difference across the mucosal membrane (Vm) measured in vitro, a maximal effect being seen at a concentration of 10(-4)M. Furthermore, the magnitude of the depolarization induced by the addition of galactose (4 mM) to the mucosal fluid was enhanced by neomycin (10(-4)M). Phlorhizin (10(-4)M) abolished the galactose-induced depolarization in both the absence and presence of the antibiotic. It is concluded that neomycin increases the electrical driving force for Na+ during Na+-coupled galactose entry into the enterocyte.
mesh_terms: D000818:Animals; D001693:Biological Transport, Active / Q000187:drug effects; D005690:Galactose / Q000378:metabolism*; D007408:Intestinal Absorption / Q000187:drug effects*; D007413:Intestinal Mucosa / Q000378:metabolism* / Q000502:physiology; D007583:Jejunum / Q000378:metabolism* / Q000502:physiology; D007700:Kinetics; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects; D009355:Neomycin / Q000494:pharmacology*; D010695:Phlorhizin / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D012964:Sodium / Q000378:metabolism
chemical_list: D012964:Sodium; D010695:Phlorhizin; D009355:Neomycin; D005690:Galactose