The Role of Ovine Conceptus Secretory Proteins in the Establishment of Pregnancy

  • Fuller W. Bazer
  • J. L. Vallet
  • C. J. Ashworth
  • R. V. Anthony
  • R. M. Roberts
Part of the Advances in Experimental Medicine and Biology book series (AEMB, volume 230)


Sheep (Ovis aries) that are not pregnant have recurring estrous cycles of about 17 days’ duration during the breeding season, i.e., August through December to January. The first day of behavioral estrus is designated Day 0 with ovulation occurring about 30h after onset of estrus and the ovulatory surge of Luteinizing Hormone (LH). The estrous cycle is characterized by growth (Days 4–12) and then regression (luteolysis) of the corpus luteum (CL). Luteolysis begins on about Day 15 after onset of estrus. Prostaglandin F2-alpha (PGF), produced by the uterine endometrium, is the uterine luteolytic hormone in sheep (1). Beginning on Days 14 to 15 and continuing until the onset of the next period of estrus, PGF is released in a pulsatile manner. About 5 episodes of PGF release per 24h are required for luteolysis (2,3).


Corpus Luteum Estrous Cycle Uterine Horn Oxytocin Receptor Uterine Endometrium 
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  1. 1.
    F. W. Bazer, J. L. Vallet, R. M. Roberts, D. C. Sharp, and W. W. Thatcher, Role of conceptus secretory products in establishment of pregnancy, J. Reprod. Fert. 76: 841 (1986).CrossRefGoogle Scholar
  2. 2.
    W. Schramm, L. Bovaird, M. E. Glew, G. Schramm, and J. A. McCracken, Corpus luteum regression induced by ultra-low pulses by prostaglandin F2-alpha, Prostaglandins 36: 347 (1983).CrossRefGoogle Scholar
  3. 3.
    L. Zarco, G. H. Stabenfeldt, G. E. Bradford, and S. Basu, A detailed study of prostaglandin F2-alpha release during luteolysis and establishment of pregnancy in the ewe, Biol. Reprod. 30 (Suppl. 1): 153, Abstract (1984).Google Scholar
  4. 4.
    R. M. Morr and L. E. A. Rowson, Local uterine mechanisms affecting luteal function in the sheep, J. Reprod. Fert. 11: 307 (1966a).CrossRefGoogle Scholar
  5. 5.
    R. M. Moor and L. E. A. Rowson, The corpus luteum of the sheep: effect of the removal of embryo on luteal function, J. Endocr. 34: 497 (1966b).PubMedCrossRefGoogle Scholar
  6. 6.
    L. E. A. Rowson and R. M. Moor, The influence of embryonic tissue homogenate infused into the uterus on the life-span of the corpus luteum in the sheep, J. Reprod. Fert. 13: 511 (1967).CrossRefGoogle Scholar
  7. 7.
    J. Martal, M. Lacroix, C. Loudes, M. Saunier, and S. Wintenberger-Torres, Trophoblastic an antiluteolytic protein present in early pregnancy in sheep, J. Reprod. Fert. 56: 63 (1979).CrossRefGoogle Scholar
  8. 8.
    W. E. Ellinwood, T. M. Nett, and G. D. Niswender, Maintenance of the corpus luteum of early pregnancy in the ewe. I. Luteotrophic properties of embryonic homogenates, Biol. Reprod. 21: 281 (1979).PubMedCrossRefGoogle Scholar
  9. 9.
    J. Martal and J. Djiane, The production of chorionic somatomammotrophin in sheep, J. Reprod. Fert. 49: 285 (1977).CrossRefGoogle Scholar
  10. 10.
    S. B. Fishel, R. G. Edwards, and C. J. Evans, Human chorionic gonadotrophin secreted by preimplantation embryos cultured in vitro, Science 223: 816 (1984).PubMedCrossRefGoogle Scholar
  11. 11.
    J. D. Godkin, F. W. Bazer, R. J. Moffatt, F. Sessions, and R. M. Roberts, Purification and properties of a major, low molecular weight protein released by the trophoblast of sheep blastocysts on Day 13-21, J. Reprod. Fert. 65: 141 (1982).CrossRefGoogle Scholar
  12. 12.
    J. D. Godkin, F. W. Bazer, and R. M. Roberts, Ovine trophoblast protein I, an early secreted blastocyst protein, binds specifically to uterine endometrium and affects protein synthesis, Endocrinol. 114: 120 (1984b).CrossRefGoogle Scholar
  13. 13.
    J. D. Godkin, F. W. Bazer, W. W. Thatcher, and R. M. Roberts, Proteins released by cultured Day 15-16 conceptuses prolong luteal maintenance when introduced into the uterine lumen of cyclic ewes, J. Reprod. Fert. 71: 57 (1984a).CrossRefGoogle Scholar
  14. 14.
    K. H. Young, F. W. Bazer, J. W. Simpkins, and R. M. Roberts, Effect of early pregnancy and acute estradiol-17beta administration on porcine uterine secretion, cyclic nucleotides and catecholamines, Endocrinol. 120:In Press (1987).Google Scholar
  15. 15.
    M. E. Wilson, G. S. Lewis, and F. W. Bazer, Proteins of ovine blastocyst origin, Biol. Reprod. 20 (Suppl. 1): 101A, Abstract (1979).Google Scholar
  16. 16.
    J. D. Godkin, F. W. Bazer, and R. M. Roberts, Protein production by cultures established from Day 14-16 sheep and pig conceptuses, J. Reprod. Fert. 74: 377 (1985).CrossRefGoogle Scholar
  17. 17.
    P. J. Hansen, R. V. Anthony, F. W. Bazer, G. A. Baumbach, and R. M. Roberts, In vitro synthesis and secretion of ovine trophoblast protein-1 during the period of maternal recognition of pregnancy, Endocrinol. 117:1424 (1985).Google Scholar
  18. 18.
    J. A. McCracken, W. Schramm, and W. C. Okulicz, Hormone receptor control of pulsatile secretion of PGF2-alpha from the ovine uterus during luteolysis and its abrogation in early pregnancy, in: Prostaglandins In Animal Reproduction II, L. E. Edquist and H. Kindahl, eds., Elsevier Science Publishers, Amsterdam (1984).Google Scholar
  19. 19.
    A. P. F. Flint and E. L. Sheldrick, Evidence for a systemic role for ovarian oxytocin in luteal regression in sheep, J. Reprod. Fert. 67: 215. (1983).CrossRefGoogle Scholar
  20. 20.
    R. J. Kittok and J. H. Britt, Corpus luteum function in ewes given estradiol during the estrous cycle or early pregnancy. J. Anim. Sci. 45: 336 (1977).PubMedGoogle Scholar
  21. 21.
    R. J. Fairclough, L. G. Moore, A. J. Peterson, and W. B. Watkins, Effect of oxytocin on plasma concentrations of 13,14-dihydro-15- keto prostaglandin F and the oxytocin associated neurophysin during the estrous cycle and early pregnancy in the ewe, Biol. Reprod. 31: 36 (1984).PubMedCrossRefGoogle Scholar
  22. 22.
    K. B. Fincher, F. W. Bazer, P. J. Hansen, W. W. Thatcher, and R. M. Roberts, Proteins secreted by the sheep conceptus suppress induction of uterine prostaglandin F-2 alpha release by oestradiol and oxytocin, J. Reprod. Fert. 76: 425 (1986).CrossRefGoogle Scholar
  23. 23.
    W. B. Watkins, L. G. Moore, A. P. F. Flint, and E. L. Sheldrick, Secretion of neurophysins by the ovary in sheep, Peptides 5: 61 (1984).PubMedCrossRefGoogle Scholar
  24. 24.
    S. B. Hooper, W. B. Watkins, and G. D. Thorburn, Oxytocin, oxytocin-associated neurophysin, and prostaglandin F2-alpha concentrations in the utero-ovarian vein of pregnant and nonpregnant sheep, Endocrinol. 119:In Press (1986).Google Scholar
  25. 25.
    A. P. F. Flint, E. L. Sheldrick, and H. J. Stewart, Oxytocin stimulates phosphatidylinositol cycle in sheep uterus in vitro, J. Endocr. 107 (Suppl. 1): 105Abstract (1985).Google Scholar
  26. 26.
    A. P. F. Flint and E. L. Sheldrick, Continuous infusion of oxytocin prevents induction of uterine oxytocin receptor and blocks luteal regression in cyclic ewes, J. Reprod. Fert. 75: 623 (1985).CrossRefGoogle Scholar
  27. 27.
    R. J. Mapletoft, M. R. Del Campo, and O. J. Ginther, Unilateral luteotrophic effect of uterine venous effluent of a gravid uterine horn in sheep, Proc. Soc. Exp. Biol. Med. 150: 129 (1975).PubMedGoogle Scholar
  28. 28.
    W. J. Silvia, J. S. Ottobre, and E. K. Inskeep, Concentrations of prostaglandins E2, F2-alpha and 6-keto-prostaglandin Fl-alpha in the utero-ovarian venous plasma of nonpregnant and early pregnant ewes, Biol. Reprod. 30: 936 (1984).PubMedCrossRefGoogle Scholar
  29. 29.
    E. L. Sheldrick and A. P. F. Flint, Transient uterine refractoriness after oxytocin administration in ewes, J. Reprod. Fert. 77: 523 (1986).CrossRefGoogle Scholar
  30. 30.
    J. E. Flechon, M. Guillomot, M. Charlier, B. Flection, and J. Martal, Experimental studies on the elongation of the ewe blastocyst, Reprod. Nutr. Develop. 26: 1017 (1986).CrossRefGoogle Scholar
  31. 31.
    S. D. Helmer, P. J. Hansen, R. V. Anthony, W. W. Thatcher, F. W. Bazer, and R. M. Roberts, Identification of bovine trophoblast protein-1, a secretory protein immunologically related to ovine trophoblast protein-1, J. Reprod. Fert. 79:In Press (1985).Google Scholar

Copyright information

© Plenum Press, New York 1987

Authors and Affiliations

  • Fuller W. Bazer
    • 1
    • 2
  • J. L. Vallet
    • 1
    • 2
  • C. J. Ashworth
    • 1
    • 2
  • R. V. Anthony
    • 1
    • 2
  • R. M. Roberts
    • 1
    • 2
  1. 1.University of FloridaGainesvilleUSA
  2. 2.University of MissouriColumbiaUSA

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