AJP - Gastrointestinal and Liver Physiology, Vol 265, Issue 3 514-G520, Copyright © 1993 by American Physiological Society
Transcriptional and posttranscriptional control in synthesis of growth marker polypeptides in mouse parotids
R. O. Lopez Solis, M. J. Gonzalez, L. Castillo, S. Pena y Lillo and C. Alliende
Department of Cell Biology and Genetics, Faculty of Medicine, University of Chile, Santiago.
The chronic daily administration of isoproterenol provokes in mouse parotid
glands the induction and progressive accumulation of a family of secretory
polypeptides named polypeptides C, D, E, F, and G (polypeptides C-G). These
polypeptides, which seem to be part of the family of proline-rich proteins,
have been considered as molecular markers of the growth-in-size response in
the mouse parotid acinar cells. In the present study, two pharmacological
approaches were used to determine whether the induction and the
postsecretory reappearance of polypeptides C-G may be distinguished from
each other. First, actinomycin D, a transcriptional inhibitor, was found to
interfere with the induction by isoproterenol but not with the
postsecretory reappearance. Second, pilocarpine, a secretagogue that was
found to be a very weak inducer of polypeptides C-G, was able to provoke
secretion and then reappearance of the whole group of isoproterenol-induced
polypeptides. Accordingly, these data suggest that the induction of
polypeptides C-G is dependent on transcriptional activity and that it is
unrelated to secretion stimulation. By contrast, the postsecretory
reappearance of polypeptides C-G may occur even when transcriptional
activity is inhibited and it would be related to the secretory activity.
