Experimental modification of rat pituitary prolactin cell function
during and after spaceflight.
Hymer, W. C., T. Salada, L. Avery, and R. E. Grindeland.
Department of Biochemistry and Molecular Biology, The Pennsylvania
state University, University Park, PA 16802, NASA Ames Research
Center, Moffett Field, CA 94035
APStracts 2:0519A, 1995.
This study was done to evaluate the effects of microgravity on
prolactin (PRL) cells of the male rat pituitary gland. We used the
identical passive closed vial cell culture system that was described
in a companion report for the culture of growth hormone cells (W. C.
Hymer, J. Appl. Physiol., submitted). After an 8 day spaceflight all
flight media (containing released PRL), as well as extracts
(containing intracellular PRL) contained significantly lower amounts
of immunoreactive PRL than their corresponding ground controls. On
the other hand, these same samples, when assessed for their
biological activities by two different in vitro lymphocyte assays,
yielded disparate results which may reflect posttranslational
modifications to the hormone molecule. Other data showed that 1) the
apparent molecular weights of released PRL molecules were not altered
by microgravity but 2) the region from which the PRL cells came
(dorsal/ventral) made a significant difference in the amount and
activity of PRL released from the flight cells. Because there is much
current interest in the role that PRL may play in the regulation of
immune system, and because changes in both cellular and humoral
immunity accompany spaceflight, this study could help define future
microgravity research in this area.
Received 18 January 1995; accepted in final form 28 September
1995.
APS Manuscript Number A58-5.
Article publication pending Journal of Applied Physiology.
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 8 December 95