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Characterization of Oxytocin Receptors in Corpus Luteum Endothelial Cells. Katy McHenry & Dr. Fredrick Stormshak Department of Animal Sciences Oregon State University. Background. Bovine Estrous Cycle = 21 days One egg matures Released as an oocyte
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Characterization of Oxytocin Receptors in Corpus Luteum Endothelial Cells Katy McHenry & Dr. Fredrick Stormshak Department of Animal Sciences Oregon State University
Background • Bovine Estrous Cycle = 21 days • One egg matures • Released as an oocyte • Granulosa cells of the empty follicle turn into the corpus luteum • Angiogenesis • Endocrine Gland
Oxytocin • Smooth muscle contraction in uterus during childbirth • Roll in maternal instinct and building relationships? Stimulation of milk letdown
Hypothesis Bovine luteal oxytocin acts locally to stimulate the proliferation and migration of endothelial cells to form the vascular system of the developing corpus luteum.
1.Block oxytocin receptors Importance Corpus Luteum can not form Progesterone 2. Tumor angiogenesis and growth
Procedure 1. Isolate the endothelial cells 2. Measure the binding of oxytocin to endothelial cell oxytocin receptors
Isolating Endothelial Cells Remove corpus luteum eight days post-estrus • Check cows for estrus using vasectomized bull
Dissociate corpus luteum using collagenase and DNAse • Tosyl-activated magnetic beads • Couple with lectin BS-1 • Add dissociated tissue and separate endothelial cells
radioreceptor Assay for oxytocin binding [ H]-Oxytocin & 200 fold excess unlabeled Oxytocin • [ H]-Oxytocin 3 3
New Theory • Pericyte Cells • Stem Cells Smooth Muscle
Summary • Oxytocin showed slight binding to receptors on endothelial cells in the corpus luteum. • Hypothesis was not strongly supported • Large amount of oxytocin binding to receptors on non-endothelial luteal cells • Possibly pericyte cells?
Thank you • Dr. Fred Stormshak • Oregon State University, Department of Animal Sciences • Oregon State University, Honors College • Dr. Kevin Ahern • The Howard Hughes Medical Institute