Discordance of prolactin gene transcription, mrna storage and
hormone release within individual mammotropes.
Casta-O, J. P., W. J. Faught, E. E. Glav, B. S. Russell, and L. S.
Frawley.
Department of Cell Biology and Anatomy, Medical University of South
Carolina, Charleston, South Carolina 29425
APStracts 3:0228E, 1996.
The mammotrope has traditionally been a favored model for studies of
hormonal gene expression, biosynthesis and release. However, the
primary site(s) at which these processes are coordinated and
integrated remains to be established. Because there is considerable
indirect evidence to suggest that the rate of PRL secretion is
dictated, in large part, at the level of transcription, the relative
contribution of other putative regulatory foci has received less
attention. The purpose of the present study was to test the primacy
of transcriptional regulation at the single cell level. To this end,
we quantified within individual mammotropes the relationship between
PRL gene transcription, mRNA storage and hormone release. This was
accomplished by the combined application of "real-time"
measurement of gene expression, in situ hybridization cytochemistry,
and reverse hemolytic plaque assay, respectively. Our results
demonstrate a quantitative dissociation among these variables
suggesting that control mechanisms besides transcription play a
primary role in integrating and coordinating flow through the PRL
secretory pathway.
Received 19 July 1996; accepted in final form 22 October 1996.
APS Manuscript Number E346-6.
Article publication pending Am. J. Physiol. (Endocrinol. Metab.).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 13 November 1996