Previously, it was reported that chronic intra-uterine infusion of PGE 1 or PGE 2 every four hours inhibited luteolysis in ewes. However, estradiol-17β or PGE 2 given intra-uterine every 8 h did not inhibit luteolysis in heifers, but infusion of estradiol + PGE 2 inhibited luteolysis in heifers. The objective of this experiment was to determine whether and how intra-luteal implants containing PGE 1 or PGE 2 prevent luteolysis in Angus or Brahman cows. On day-13 post-estrus, Angus cows received no intra-luteal implant and corpora lutea were retrieved or Angus and Brahman cows received intra-luteal silastic implants containing Vehicle, PGE 1, or PGE 2 and corpora lutea were retrieved on day-19. Coccygeal blood was collected daily for analysis for progesterone. Breed did not influence the effect of PGE 1 or PGE 2 on luteal mRNA for LH receptors or unoccupied or occupied luteal LH receptors did not differ (P > 0.05) so the data were pooled. Luteal weights of Vehicle-treated Angus or Brahman cows from days-13-19 were lower (P < 0.05) than those treated with intra-luteal implants containing PGE 1 or PGE 2. Day-13 Angus luteal weights were heavier (P < 0.05) than Vehicle-treated Angus cows on day-19 and luteal weights of day-13 corpora lutea were similar (P > 0.05) to Angus cows on day-19 treated with intra-luteal implants containing PGE 1 or PGE 2. Profiles of circulating progesterone in Angus or Brahman cows treated with intra-luteal implants containing PGE 1 or PGE 2 differed (P < 0.05) from controls, but profiles of progesterone did not differ (P > 0.05) between breeds or between cows treated with intra-luteal implants containing PGE 1 or PGE 2. Intra-luteal implants containing PGE 1 or PGE 2 prevented (P < 0.05) loss of luteal mRNA for LH receptors and unoccupied or occupied receptors for LH compared to controls. It is concluded that PGE 1 or PGE 2 alone delays luteolysis regardless of breed. We also conclude that either PGE 1 or PGE 2 prevented luteolysis in cows by up-regulating expression of mRNA for LH receptors and by preventing loss of unoccupied and occupied LH receptors in luteal tissue.
|Number of pages||10|
|Journal||Prostaglandins and Other Lipid Mediators|
|State||Published - Aug 2011|
Bibliographical noteFunding Information:
The authors would like to thank Mr. Wayne Toma (University of Hawaii) for assistance with statistical analysis and graphics. Antisera for progesterone were kindly provided by Dr. R.L. Butcher, West Virginia University, Morgantown, West Virginia. This paper is dedicated to the memory of Dr. Hal R. Behrman who has been a long time collaborator with Dr. Weems. This work was supported by USDA-CSREES Special Grants Program (TSTAR) administrated by the Pacific Basin Advisory Group (PBAG) grant to C.W. Weems (CSREES 2006-04752) and USDA Regional Research Project W-112 to C.W. Weems (HAW-259) at the CollegeTropical Agriculture and Human Resources.
- Corpus luteum
- LH receptors
- mRNA LH receptors
ASJC Scopus subject areas
- Cell Biology