This proposal will investigate the physiological role of binding sites for platelet-activating factor (PAF), a glycerophospholipid, with potent smooth-muscle stimulating and vascular permeability inducing properties. It is hypothesized that PAF may be intimately involved in several events in the pre-implantation stage of pregnancy and in the preparation of the uterus for implantation.
The specific aims are to: 1) characterize the binding parameters of these PAF specific sites in rabbits, by comparing binding affinities and capacities of oviductal and uterine tissues in pregnant and pseudopregnant rabbits during the pre-implantation period, 2) determine how different hormonal conditions, e.g., estradiol and/or progesterone treatment affect these binding affinities and capacities in rabbits, 3) determine the presence of PAF binding sites on pre-implantation embryos, study their binding affinities and capacities in relation to embryonic growth and development, and determine their localization on the blastomeres in early stage embryos, and on the cells of the trophoblast and the inner cell mass at the blastocyst stage, 4) correlate changes in vascular permeability of the rabbit uterus with administration of synthetic PAF and the use of PAF inhibitors to block this response, 5) examine the relevance of embryoderived PAF for the ovum transport and implantation process by means of embryo transfer techniques following treatment of the embryos with synthetic PAF and PAF antagonists, 6) localize PAF binding sites in cells of rabbit and human uterine tissues, 7) determine whether dissociated human endometrial cell types (epithelial and stroma) display PAF binding similar to that measured in the rabbit, and examine the effect of steroid hormones on PAF binding in human epithelial and stromal cells in in vitro cultures. The research described above will enable us to determine in what manner PAF is involved in ovum transport and in the preparation of the uterus for implantation, and whether it is embryo-derived PAF or uterine-derived PAF which is responsible for the changes in vascular permeability that occur underlying the implanting blastocyst. Lastly, and most importantly, an initial determination will be able to be made as to whether the importance of PAF in the implantation process in the rabbit is species-specific or is of more general significance. This research will have important implications for elucidating factors operating in the pre-implantation period which may cause reduced fertility.

Project Start
1988-12-01
Project End
1991-11-30
Budget Start
1988-12-01
Budget End
1989-11-30
Support Year
1
Fiscal Year
1989
Total Cost
Indirect Cost
Name
University of Texas Health Science Center San Antonio
Department
Type
Schools of Medicine
DUNS #
800772162
City
San Antonio
State
TX
Country
United States
Zip Code
78229
Kudolo, G B; Yang, Y Q; Chen, D B et al. (1995) Differential metabolism of exogenous platelet-activating factor by glandular epithelial and stromal cells of rabbit endometrium. J Reprod Fertil 105:315-24
Norris, C J; Peairs, W A; Kudolo, G B et al. (1994) Platelet-activating factor antagonists and implantation in rabbits. J Reprod Fertil 100:395-401
Yang, Y Q; Kudolo, G B; Harper, M J (1992) Binding of platelet-activating factor to oviductal membranes during early pregnancy in the rabbit. J Lipid Mediat 5:77-96
Jones, M A; Kudolo, G B; Harper, M J (1992) Rabbit blastocysts accumulate platelet-activating factor (PAF) and lyso-PAF in vitro. Mol Reprod Dev 32:243-50
Harper, M J (1992) The implantation window. Baillieres Clin Obstet Gynaecol 6:351-71
Kudolo, G B; Harper, M J (1992) Pregnancy-associated remodeling of rabbit endometrial platelet-activating factor receptors. J Lipid Mediat 5:271-88
Jones, M A; Harper, M (1991) Rabbit blastocysts accumulate [3H]quinuclidinyl benzilate in vitro. Mol Reprod Dev 29:337-41
Kudolo, G B; Kasamo, M; Harper, M J (1991) Autoradiographic localization of platelet-activating factor (PAF) binding sites in the rabbit endometrium during the peri-implantation period. Cell Tissue Res 265:231-41
Kudolo, G B; Harper, M J (1990) Estimation of platelet-activating factor receptors in the endometrium of the pregnant rabbit: regulation of ligand availability and catabolism by bovine serum albumin. Biol Reprod 43:368-77
Kudolo, G B; Harper, M J (1989) Characterization of platelet-activating factor binding sites on uterine membranes from pregnant rabbits. Biol Reprod 41:587-603

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