JDS
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Interpretive Summary
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Ushida, Y.
Right arrow Articles by Takase, M.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Ushida, Y.
Right arrow Articles by Takase, M.
J. Dairy Sci. 90:541-546
© American Dairy Science Association, 2007.

Bovine {alpha}-Lactalbumin Stimulates Mucus Metabolism in Gastric Mucosa

Y. Ushida*,1, Y. Shimokawa*, T. Toida*, H. Matsui{dagger} and M. Takase*

* Biochemical Research Laboratory, Morinaga Milk Industry Co. Ltd., Zama, Kanagawa 228-8583, Japan
{dagger} Institute of Clinical Medicine, University of Tsukuba, Tsukuba, Ibaraki 305-8575, Japan

1 Corresponding author: y_usida{at}morinagamilk.co.jp

Bovine {alpha}-lactalbumin ({alpha}-LA), a major milk protein, exerts strong gastroprotective activity against rat experimental gastric ulcers induced by ethanol or stress. To elucidate the mechanisms underlying this activity, the influence of {alpha}-LA on gastric mucus metabolism was investigated in vitro and in vivo. For the in vitro study, RGM1 cells (a rat gastric epithelial cell line) were selected for observation of the direct activity of {alpha}-LA on gastric mucosal cells and cultured in the presence of either {alpha}-LA or ovalbumin (OVA), a reference protein showing no gastroprotective activity. Amounts of synthesized and secreted mucin, a major component of mucus, were determined using [3H]glucosamine as a tracer, and prostaglandin E2 (PGE2) levels in the culture medium were determined by RIA. For the in vivo study, the thickness of the mucus gel layer, a protective barrier for gastric mucosa, was evaluated histochemically in rat gastric mucosa. {alpha}-Lactalbumin (3 mg/mL) significantly stimulated mucin synthesis and secretion in RGM1 cells and also increased PGE2 levels in the culture medium. In contrast, OVA showed no enhancing effects under identical conditions. Neither indomethacin, a cyclo-oxygenase inhibitor, nor AH23848, a prostaglandin EP4 receptor antagonist, affected {alpha}-LA-induced enhancement of mucin synthesis and secretion. In vivo, oral administration of {alpha}-LA (300 mg/kg x 3 times/d x 7 d) increased the thickness of the mucus gel layer in rats. These results indicate that {alpha}-LA fortifies the mucus gel layer by stimulating mucin production and secretion in gastric mucus-producing cells, and that this enhancing effect is independent of endogenous PGE2. Comparison of the efficacy of {alpha}-LA with OVA suggests that the activities observed in RGM1 cells are closely related to the gastroprotective effects in rat gastric ulcer models. In conclusion, {alpha}-LA stimulates mucus metabolism, and this action may be responsible for its gastroprotective activity.

Key Words: {alpha}-lactalbumin • mucus • prostaglandin • gastroprotective activity




This article has been cited by other articles:


Home page
 J DAIRY SCIHome page
J. Wang, P. Yang, B. Tang, X. Sun, R. Zhang, C. Guo, G. Gong, Y. Liu, R. Li, L. Zhang, et al.
Expression and Characterization of Bioactive Recombinant Human {alpha}-Lactalbumin in the Milk of Transgenic Cloned Cows
J Dairy Sci, December 1, 2008; 91(12): 4466 - 4476.
[Abstract] [Full Text] [PDF]


HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Copyright © 2007 by the American Dairy Science Association ®.