1. Katy McHenry & Dr. Fredrick Stormshak Department of Animal Sciences Oregon State University

2. 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

5.  Stimulation of milk letdown  Smooth muscle contraction in uterus during childbirth  Roll in maternal instinct and building relationships?

7. Bovine luteal oxytocin acts locally to stimulate the proliferation and migration of endothelial cells to form the vascular system of the developing corpus luteum.

8. 1. Block oxytocin receptors Corpus Luteum can not form 2. Tumor angiogenesis and growth Progesterone

9. 1. Isolate the endothelial cells 2. Measure the binding of oxytocin to endothelial cell oxytocin receptors

10. Remove corpus luteum eight days post-estrus Remove corpus luteum eight days post-estrus Check cows for estrus using vasectomized bull Check cows for estrus using vasectomized bull

11.  Dissociate corpus luteum using collagenase and DNAse  Tosyl-activated magnetic beads  Couple with lectin BS-1  Add dissociated tissue and separate endothelial cells

12.  [ H]-Oxytocin & 200 fold excess unlabeled Oxytocin [ H]-Oxytocin  [ H]-Oxytocin 3 3

14. Results

15. Results

16. New Theory  Pericyte Cells  Stem Cells Smooth Muscle

17. Results

18. 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?

19.  Dr. Fred Stormshak  Oregon State University, Department of Animal Sciences  Oregon State University, Honors College  Dr. Kevin Ahern  The Howard Hughes Medical Institute