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Tryptophan modulates exocrine secretory function in rat pancreatic acini.

Authors :
Okutani, Toshio
Okabayashi, Yoshinori
Koide, Makoto
Matsushita, Kenji
Fujii, Masatoshi
Hasegawa, Hiroshi
Kido, Yoshiaki
Otsuki, Makoto
Kasuga, Masato
Source :
Journal of Gastroenterology; Mar1996, Vol. 31 Issue 2, p254-259, 6p
Publication Year :
1996

Abstract

We investigated the effect of tryptophan (Trp) on exocrine secretory function, using isolated rat pancreatic acini. Trp inhibited cholecystokinin-octapeptide (CCK-8)-stimulated amylase secretion, causing a downward shift in the dose-response curve. The inhibitory effect of Trp was dose-dependent and was observed only on the sustained secretion, there being no effect on the initial phase of amylase secretion. Trp (10 mM) also inhibited amylase secretion in response to carbachol and bombesin, as well as fluoride, a potent activator of guanine-nucleotide binding proteins. Since Ca influx is necessary for sustained secretion, we examined the effect of Trp on Ca influx and efflux. Trp increased the CCK-8-stimulated Ca influx rate without affecting Ca efflux, suggesting that Trp elevates intracellular Ca levels. Increasing intracellular Ca levels with A23187 resulted in the inhibition of CCK-8-stimulated amylase secretion. These results indicate that Trp inhibits CCK-stimulated sustained amylase secretion, in part by increasing Ca influx into acinar cells. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
09441174
Volume :
31
Issue :
2
Database :
Complementary Index
Journal :
Journal of Gastroenterology
Publication Type :
Academic Journal
Accession number :
71069349
Full Text :
https://doi.org/10.1007/BF02389526