Localization and Distribution of Platelet Activating Factor Receptors in the Mouse Ovary and Oviduct During the Estrous Cycle and Early Pregnancy


Address reprints requests to Michael Legge, Department of Biochemistry, University of Otago, PO Box 56, Dunedin, New Zealand.
E-mail: mike.legge@stonebow.otago.ac.nz


PROBLEM: This study determined platelet activating factor (PAF) binding to ovaries and oviduct tissues to identify the location of PAF–tissue interaction.
METHOD: Mouse ovaries and oviducts taken during the estrous cycle and days 1, 4 and 7 post-conception (pc) were analyzed by [


H]PAF binding using frozen sections and autoradiography.
RESULTS: For the outer epithelium of estrous and metestrous ovaries there was no significant difference in PAF binding (P>0.05); however, both stages were significantly different from proestrous (P<0.001). Ovarian stroma PAF binding was significantly higher (P<0.001) at estrous than metestrous, with no PAF binding at proestrous. Binding of PAF to estrous ovarian follicles was significantly greater (P<0.001) than at proestrous and metestrous. Estrous oviduct binding of PAF was significantly increased for stroma, inner epithelium and lumen (P<0.001 in all cases). At days 1 and 7 pc, all ovarian tissues had the greatest PAF binding with day 4 pc failing to bind PAF except for a significant decrease in corpora luteal binding (P<0.001). Oviduct binding of PAF was greatest at day 1 pc.
CONCLUSION: Ovarian and oviduct PAF receptor expression corresponds to peak embryo PAF synthesis and establishes the basis for PAF–PAF receptor mediated early pregnancy signaling system.