AJP - Endocrinology and Metabolism, Vol 272, Issue 5 E832-E840, Copyright © 1997 by American Physiological Society
Prostaglandin-endoperoxide H synthase-2 expression and activity increases with term labor in human chorion
J. E. Mijovic, T. Zakar, T. K. Nairn and D. M. Olson
Department of Physiology, University of Alberta, Edmonton, Canada.
We investigated the changes in prostaglandin-endoperoxide H synthase (PGHS)
specific activity and the levels and distribution of PGHS-1 and PGHS-2 mRNA
in chorion collected at term before the onset of labor (CS) and after term
labor and delivery (SL). PGHS specific activity and PGHS-2 mRNA abundance
were higher in chorion collected after SL compared with that obtained at CS
(P < 0.001); there was no difference in the levels of PGHS-1 mRNA
between CS and SI, tissues. The increase in PGHS specific activity at SL
was significantly correlated with PGHS-2 mRNA expression (P < 0.05) but
not with PGHS-1 mRNA levels. In situ hybridization indicated that the
pervasiveness of staining for PGHS-1 mRNA throughout full-thickness
membranes did not change with labor onset; however, a greater number of
cells expressed PGHS-2 in SL tissues. Our results demonstrate a selective
increase in PGHS-2 expression and activity in chorion trophoblasts and
mesenchymal cells with term labor onset. These observations are similar to
those concerning amnion and imply that a concerted mechanism may exist in
the fetal membranes to induce PGHS-2 expression at labor.
