Decidual prolactin-related protein: Biochemical and biological characterization and patterns of gene expression during pregnancy

The success of pregnancy in the rat requires the generation of a specialized maternal structure within the uterus, the deciduum. A number of important functions have been attributed to decidua including controlling maternal and fetal adaptations to pregnancy through the production of hormones. The present study focuses on a recently identified hormone produced by decidual cells, termed decidual prolactin-related protein (dPRP). dPRP is a glycoprotein with structural homology to a family of hormones related to pituitary prolactin (PRL).;The purpose of this study is to characterize dPRP protein, examine the biological actions of dPHP, and investigate the distribution of dPRP. We accomplished the task of obtaining large quantities of protein by generating recombinant dPRP protein. The purified recombinant dPRP was used to produce polyclonal antibodies in rabbits. Through the use of the dPHP antibodies and the recombinant dPRP protein, we were able to show that recombinant dPRP had biochemical characteristics similar to native dPRP. Additional characterization of dPRP demonstrated that it was capable of binding heparin and at least a portion of synthesized dPRP resides within the extracellular matrix. Other experiments revealed that dPRP does not bind to PRL receptors, and does not stimulate proliferation of Nb;Identifying the cellular origin and temporal characteristics of dPRP expression during pregnancy was a primary goal of this study. Our experiments revealed that dPRP expression is first detected at day 6 of pregnancy, increases with the development of the deciduum and declines with decidual regression. The expression of the dPRP protein and mRNA is predominantly localized to the antimesometrial deciduum. As expression in the deciduum wanes, expression in the junctional zone of the chorioallantoic placenta begins.;In summary, we were able to generate a recombinant dPRP with similar biochemical characteristics to native dPRP, determine the localization and time of expression of dPRP, and show that the biological actions of dPRP are not through the PRL signaling pathway and appear to be different than those of PRL.