EXPRESSION OF PLATELET-ACTIVATING-FACTOR RECEPTOR IN THE HAMSTER OVIDUCT - LOCALIZATION TO THE ENDOSALPINX

Platelet-activating factor (PAF) is a lipid mediator that has a range of biological effects on various cells and tissues. PAF-like activity has been detected in the spent media of two-cell to morula stage hamst er embryos, leading to the suggestion that PAF may be the embryonic si gnal that hastens embryo transport to the uterus in this species. The present study was undertaken to examine whether the PAF receptor (PAFr ) gene is expressed in hamster oviduct, and to identify the cell types in which the gene is expressed. DNA fragments complementary to the co ding region of mRNA encoding hamster PAFr were cloned by reverse trans cription-polymerase chain reaction (RT-PCR), identified by sequencing and used to prepare hamster specific cRNA probes. The presence of mRNA transcripts encoding the PAFr receptor in the oviduct was investigate d by subjecting oviduct mRNA to RT-PCR. Southern blot analysis of the RT-PCR products verified the identity of the presumptive PAFr cDNAs. T he cloned cDNA fragment of hamster PAFr was found to be highly conserv ed with respect to the receptor of other species, having 94.3% sequenc e similarity to the rat PAFr receptor. Hybridization histochemistry de monstrated that PAFr is expressed in the subepithelial cells and occas ionally in the epithelium. In conclusion, expression of PAFr in the ha mster oviduct is compatible with the proposed paracrine role of early embryo-derived PAF.