title: Presence of leptin receptors in rat small intestine and leptin effect on sugar absorption.
abstract: Leptin is involved in food intake and thermogenesis regulation. Since leptin receptor expression has been found in several tissues including small intestine, a possible role of leptin in sugar absorption by the intestine was investigated. Leptin inhibited D-galactose uptake by rat small intestinal rings 33% after 5 min of incubation. The inhibition increased to 56% after 30 min. However, neither at 5 min nor at 30 min did leptin prevent intracellular galactose accumulation. This leptin effect was accompanied by a decrease of the active sugar transport apparent Vmax (20 vs. 4.8 micromol/g wet weight 5 min) and apparent Km (15.8 vs. 5.3 mM) without any change in the phlorizin-resistant component. On the other hand, immunohistochemical experiments using anti-leptin monoclonal antibodies recognized leptin receptors in the plasma membrane of immune cells located in the lamina propria. These results indicate for the first time that leptin has a rapid inhibitory effect on sugar absorption and demonstrate the presence of leptin receptors in the intestinal mucosa.
authors.affiliation: Department of Physiology and Nutrition, University of Navarra, Pamplona, Spain. plostao@unav.es
authors.forename: M P
authors.initials: MP
authors.lastname: Lostao
authors.forename: E
authors.initials: E
authors.lastname: Urdaneta
authors.forename: E
authors.initials: E
authors.lastname: Martínez-Ansó
authors.forename: A
authors.initials: A
authors.lastname: Barber
authors.forename: J A
authors.initials: JA
authors.lastname: Martínez
mesh_terms: D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D002352:Carrier Proteins / Q000378:metabolism*; D002462:Cell Membrane / Q000737:chemistry; D005690:Galactose / Q000493:pharmacokinetics*; D007150:Immunohistochemistry; D007408:Intestinal Absorption / Q000187:drug effects*; D007413:Intestinal Mucosa / Q000737:chemistry / Q000166:cytology; D007583:Jejunum / Q000166:cytology; D007700:Kinetics; D020738:Leptin; D009004:Monosaccharide Transport Proteins / Q000378:metabolism; D010695:Phlorhizin / Q000494:pharmacology; D011506:Proteins / Q000494:pharmacology*; D051381:Rats; D011956:Receptors, Cell Surface; D054411:Receptors, Leptin
chemical_list: D002352:Carrier Proteins; D020738:Leptin; D009004:Monosaccharide Transport Proteins; D011506:Proteins; D011956:Receptors, Cell Surface; D054411:Receptors, Leptin; D010695:Phlorhizin; D005690:Galactose