1. Animal Science 434 Lecture 11:The Luteal Phase of the Estrous Cycle

2. Luteolysis P 4 Production (Diestrus) P 4 Production (Diestrus) CL Formation (Metestrus) Relative Progesterone Levels (Blood) Follicular Phase Luteal Phase Ovulation

3. steroid synthesis –progesterone collagenase –theca interna

4. present 1-3 days following ovulation blood vessels in follicle wall rupture walls collapse cells intermix old basement membrane becomes connective tissue of CL

5. increases in size –papilla forms composed of cells from the granulosa and theca interna progesterone production increases a small cavity may be present where the folliclular antrum was present

7. Bovine Luteal Anatomy

10. Ovine Luteal Anatomy

13. Swine Luteal Anatomy

15. Equine Luteal Anatomy

17. Luteal Tissue Large cells from granulosa Small cells from the theca interna Large cells from granulosa Small cells from the theca interna

19. Mitochondria Secretory Granules - Oxytocin - Relaxin

20. Functional Capability of CL the number of luteal cells –large cells undergo hypertrophy (3 fold) –small cells undergo hyperplasia (5 fold) vascularization of CL –Initiated by angiogenic factors from follicle –Vascularity effects CL steroid synthesis and delivery of hormones Insufficient CL function –Failure to maintain pregnancy –Important in domestic animals the number of luteal cells –large cells undergo hypertrophy (3 fold) –small cells undergo hyperplasia (5 fold) vascularization of CL –Initiated by angiogenic factors from follicle –Vascularity effects CL steroid synthesis and delivery of hormones Insufficient CL function –Failure to maintain pregnancy –Important in domestic animals

21. Progesterone Targets

22. Action of Progesterone reduces GnRH pulse amplitude and frequency prevents behavioral Estrus stops the preovulatory LH surge reduces mymetrial tone stimulates endometrial gland development and secretion stimulates aveolar development in mammary gland reduces GnRH pulse amplitude and frequency prevents behavioral Estrus stops the preovulatory LH surge reduces mymetrial tone stimulates endometrial gland development and secretion stimulates aveolar development in mammary gland

23. Progesterone Production by Luteal Cells

24. Luteolysis Uterus PGF 2  Oxytocin Uterus PGF 2  Oxytocin

25. Luteolysis in Cows, Ewes, Sows

26. Luteolysis Uterus PGF 2  Oxytocin Uterus PGF 2  Oxytocin

27. Prostaglandin F2  Control of Luteolysis Progesterone from CL stimulates production of uterine PGF2  after day 15 in cow Uterine Horn Uterine Vein Prostaglandin synthesis by uterine endometrium is released into the uterine vein. Oviduct Ovary Corpus Luteum PGF2  is picked up by ovarian artery through counter current exchange and delivered back to the ovary where it causes lysis of the CL Uterine Artery Ovarian Pedicle PGF PGF into Artery

28. Luteolysis in Mares 50% of CL’s maintained CL regresses on day 17 %50 of CL’s maintained CL maintained >30 days

29. Blood Supply to Uterus and Ovary in the Mare

30. PGF Not Effective (Cow, Ewe) PGF Not Effective (Sow)

31. Luteolysis Uterus PGF 2  Oxytocin Uterus PGF 2  Oxytocin

34. Relationship of Oxytocin and PGF2  Uterus Ovary CL PGF2  Anterior Pituitary Posterior Pituitary Oxytocin

35. Luteolysis decreased blood flow cellular response –apoptosis –progesterone synthesis Immune response –Lymphocytes –Macrophages decreased blood flow cellular response –apoptosis –progesterone synthesis Immune response –Lymphocytes –Macrophages

36. ER IP 3 Ca ++

37. Luteolysis decreased blood flow cellular response –apoptosis –progesterone synthesis Immune response –Lymphocytes –Macrophages decreased blood flow cellular response –apoptosis –progesterone synthesis Immune response –Lymphocytes –Macrophages

38. Menstrual Cycle

39. FSH LH Estradiol Progesterone Follicle Ovulation Corpus Luteum Corpus Albicans 2468101416182022242628212 Anterior Pituitary Hormones Ovarian Hormones Ovary Uterine Endo- metrium Recruitment Selection Dominance Recruitment

40. Luteolysis in the Primate Does not require the uterus CL lifespan in the human is 12-14 days unless pregnancy occurs –In the absence of pregnancy, CL self destructs

41. FSH LH Estradiol Progesterone Follicle Ovulation Corpus Luteum 2468101416182022242628212 Anterior Pituitary Hormones Ovarian Hormones Ovary Uterine Endo- metrium Menses 5 days 5 days 5 days 5 days Follicular Phase 9 days Luteal Phase 14 days

42. Variation in Menstrual Cycle Length 35-day cycle Ovulation 14 days Menses Foll. PhaseLuteal Phase Menses 28-day cycle Menses Luteal Phase Menses Foll. Phase 25-day cycle Menses Foll. Phase Menses Luteal Phase 14 days 5 days 6 days 9 days 16 days 14 days Breast Tenderness Breast Tenderness

43. Menstural Cycle Length AGE  Length  15 - 19 year olds 35 days  30 year olds 30 days  35 year olds 28 days  Variation  More in teenagers  Less in women in peak reproductive years

44. Hypothalamus GnRH Anterior Pituitary Anterior Pituitary CLFollicle Ovary LH, FSH LH LH, FSH Inhibin (-) Estradiol (-) Progesterone

45. Hypothalamus GnRH Anterior Pituitary Anterior Pituitary Follicle Ovary LH, FSH Inhibin (-) Estradiol (+)

46. Estradiol pg/ml LH mIU/ml FSH mIU/ml Prog. ng/ml