Expression of angiopoietin (ANPT)-1, ANPT-2 and their receptors in dominant follicles during periovulatory period in GnRH-treated cow.
Ovarian follicular vasculature is involved in follicular development and ovulation. Angiopoietin (ANPT)-Tie system is important for vascularization of the tissue surrounding the developing follicles and corpus luteum (CL). To determine how the expression of ANPT-1, ANPT-2 and their receptors in the follicles would be associated with the ovulatory process, the present study was conducted to examine mRNA expressions of ANPT-1, ANPT-2 and their receptors during the periovulatory phase in gonadotrophin-releasing hormone (GnRH)-treated cows. The ovaries were collected by transvaginal ovariectomy (n = 5, cows/group) and the follicles (n = 5, one follicle/cow) were classified into following groups: before GnRH administration [before luteinizing hormone (LH) surge]; 3-5 h after GnRH (during LH surge); 10 h after GnRH; 20 h after GnRH; 25 h after GnRH (peri-ovulation); and early CL (days 2-3). The mRNA expression was analysed by quantitative real-time PCR (rotor-gene 3000). Angiopoietin-1 expression rapidly decreased at 3-5 h and kept low level at 10 h after GnRH treatment compared with that before GnRH, and returned to the level before LH surge in the follicles >20 h after GnRH treatment. The levels of ANPT-2 mRNA decreased at 10 and 25 h after treatment compared with other periods. The ratio of ANPT-2/ANPT-1 (an index for destabilization of blood vessels) increased in the follicles at 3-5 h after GnRH treatment only. Both of Tie-1 and Tie-2 receptor expressions decreased in the follicles at 25 h after GnRH treatment. The results of the present study indicated that mRNA expressions of ANPT-1, ANPT-2 and their receptors changed in the bovine follicles during periovulatory period. These results suggest that angiopoietin-Tie system is associated with the initiation of vasculature of follicle that grows towards ovulation.
Shimizu
T
T
Graduate school of animal and food hygiene, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Japan.
Berisha
B
B
Schams
D
D
Miyamoto
A
A
D042683:Angiopoietin-1 / Q000235:genetics / Q000378:metabolism*; D042702:Angiopoietin-2 / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D002417:Cattle / Q000378:metabolism / Q000502:physiology*; D005260:Female; D005786:Gene Expression Regulation; D007987:Gonadotropin-Releasing Hormone / Q000494:pharmacology; D007986:Luteinizing Hormone / Q000097:blood; D006080:Ovarian Follicle / Q000254:growth & development* / Q000378:metabolism; D010060:Ovulation / Q000502:physiology*; D012333:RNA, Messenger / Q000378:metabolism; D042810:Receptor, TIE-1 / Q000235:genetics / Q000378:metabolism; D042787:Receptor, TIE-2 / Q000235:genetics / Q000378:metabolism; D042764:Receptors, TIE / Q000235:genetics / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000662:veterinary
D042683:Angiopoietin-1; D042702:Angiopoietin-2; D012333:RNA, Messenger; D007987:Gonadotropin-Releasing Hormone; D007986:Luteinizing Hormone; D042810:Receptor, TIE-1; D042787:Receptor, TIE-2; D042764:Receptors, TIE