AJP - Gastrointestinal and Liver Physiology, Vol 267, Issue 2 220-G226, Copyright © 1994 by American Physiological Society
Activin A: negative regulator of amylase secretion and cell proliferation in rat pancreatic acinar AR42J cells
H. Yasuda, S. Tanaka, H. Ohnishi, H. Mashima, N. Ogushi, T. Mine and I. Kojima
Cell Biology Research Unit, Gunma University, Maebashi, Japan.
Activin A, a member of the transforming growth factor-beta supergene
family, exists in secretory granules of non-B-cells of rat pancreatic islet
(H. Yasuda, K. Inoue, H. Shibata, T. Takeuchi, Y. Eto, Y. Hasegawa, N.
Sekine, Y. Totsuka, T. Mine, E. Ogata, and I. Kojima. Endocrinology 133:
624-630, 1993). Because functions of exocrine pancreas are influenced by
hormones in pancreatic islet, it is possible that activin A affects the
function of pancreatic acinar cells. To examine this possibility, we
studied the effects of activin A on amylase secretion and DNA synthesis in
AR42J cells. In these cells, dexamethasone (Dx) induces increases in
secretory organelles and secretion of amylase (C. D. Logsdon, J. Moessner,
J. A. Williams, and I. D. Goldfine. J. Cell Biol. 100: 1200-1208 1985).
Activin A did not change the rate of amylase release by itself nor affect
the cholecystokinin-stimulated amylase release from Dx-treated
differentiated AR42J cells. However, when activin A was added together with
Dx, activin A inhibited Dx-induced increase in amylase content in a
dose-dependent manner. In the presence of 1 nM activin A, the effect of Dx
was abolished. In the absence of Dx, amylase content of the cells was also
reduced by activin A in a dose-dependent manner. The maximum inhibitory
effect was obtained by 10 nM activin A, and at this concentration amylase
content became undetectable. In addition, activin A potently inhibited DNA
synthesis as assessed by [3H]thymidine incorporation.(ABSTRACT TRUNCATED AT
250 WORDS)
