Progesterone exposure of the preovulatory follicle in the seasonally anestrous ewe alters the expression of angiogenic growth factors in the early corpus luteum

Ana Carolina Martinelli Christensen, W. Haresign, M. Khalid

Research output: Contribution to journalArticlepeer-review

7 Citations (SciVal)

Abstract

Gonadotrophin releasing hormone (GnRH)-induced ovulation in seasonally anestrous ewes is associated with a high incidence of defective corpora lutea (CL), which can be completely eliminated by priming ewes with progesterone before GnRH treatment, but the physiological basis of this has remained elusive. This study tested the hypothesis that progesterone priming eliminates defective luteal function by altering the expression of Vascular Endothelial Growth Factor (VEGF), its receptor VEGFR-2, and angiopoietin (ANG)-1, ANG-2 and their receptorTIE-2 in the early CL. Fifteen seasonally anestrous ewes were treated by i.m. injection with 20 mg of progesterone 3 days before the start of GnRH treatment, while another 15 animals served as controls. Intravenous injections of 500 ng GnRH were given to all the ewes every 2 h for 28 h, followed by a 300 g GnRH bolus injection to synchronize the preovulatory luteinizing hormone (LH) surge. Corpora lutea were collected 1, 2 and 4 days after ovulation and analyzed for protein and mRNA expression of VEGF, VEGFR-2, ANG-1, ANG-2 and Tie-2 using Western Immunoblotting and in situ hybridization. VEGF, VEGFR-2 and ANG-1 expression was significantly higher (P?0.05) in the CL of progesterone-primed animals compared to non-primed ones. However, no differences were observed in the ANG-2 or Tie-2 expression levels between the two treatment groups. These data suggest that progesterone priming of the preovulatory follicle alters the expression of some angiogenic growth factors in the early CL, leading to greater vascular stability and thereby normal luteal function.
Original languageEnglish
Pages (from-to)1648-1660
Number of pages13
JournalTheriogenology
Volume77
Issue number8
DOIs
Publication statusPublished - 01 May 2012

Fingerprint

Dive into the research topics of 'Progesterone exposure of the preovulatory follicle in the seasonally anestrous ewe alters the expression of angiogenic growth factors in the early corpus luteum'. Together they form a unique fingerprint.

Cite this