HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) All Versions of this Article: 293/4/G773    most recent 00260.2007v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Cammisotto, P. G. Articles by Bendayan, M. Search for Related Content PubMed PubMed Citation Articles by Cammisotto, P. G. Articles by Bendayan, M.

HORMONES AND SIGNALING

Transcytosis of gastric leptin through the rat duodenal mucosa

Department of Pathology and Cell Biology, University of Montreal, Montréal, Québec, Canada

Submitted 11 June 2007 ; accepted in final form 29 July 2007

Leptin is secreted into the gastric juice by epithelial Chief cells and reaches the duodenum in a biologically intact active form. We assessed the possibility that this gastric leptin crosses the intestinal mucosa by transcytosis through enterocytes to reach blood circulation. Endogenous gastric leptin secretion was triggered by cholinergic stimulation. In another set of experiments, recombinant leptin was inserted in vivo into the duodenal lumen. Plasma levels of leptin were assessed by enzyme immunoassay and Western blot, and duodenal tissue was processed for immunocytochemistry. We first observed that leptin was found inside duodenal enterocytes from fed rats but not inside those from fasted ones. Stimulation of gastric secretion by a cholinergic agent led to rapid increases in plasma leptin levels (202 ± 39%) except when the pylorus was clamped. Insertion of recombinant leptin into the duodenal lumen raised plasma leptin concentrations (558 ± 34%) quite rapidly, whereas carrier solution without leptin had no effect. The use of FITC-tagged leptin reinforced these results. Light and electron microscopy revealed the cellular compartments involved in its transcytosis, namely, the enterocyte microvilli, the endocytotic vesicles, the Golgi complex, and the basolateral interdigitations. Leptin was also present in the lamina propria, in capillary endothelial cell plasmalemmal vesicles, and in capillary lumina. These results demonstrate that gastric exocrine leptin is internalized by duodenal enterocytes and delivered to the lamina propria and blood circulation. It may thus be able to play important paracrine and endocrine functions for the control of gastric emptying and nutrient absorption.

duodenum; gastric emptying

This article has been cited by other articles:

				G. H. Hansen, L.-L. Niels-Christiansen, and E. M. Danielsen Leptin and the Obesity Receptor (OB-R) in the Small Intestine and Colon: A Colocalization Study J. Histochem. Cytochem., July 1, 2008; 56(7): 677 - 685. [Abstract] [Full Text] [PDF]