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(215) THE LH/FSH SURGE INCREASES THE EXPRESSION OF mRNA FOR ADAMTS SUBTYPES IN THECA INTERNA OF BOVINE PERIOVULATORY FOLLICLES. Willis, E.1, Bridges, P.1, Fortune, J.1, 1 Cornell University, Ithaca, NY ABSTRACT- ADAMTS (A Disintegrin And Metalloproteinase with ThromboSpondin motifs) is a recently described family of extracellular proteases that play important regulatory roles in extracellular matrix remodeling. The periovulatory period is accompanied by proteolysis and extensive remodeling of the apex of the preovulatory follicle and surrounding tissue. Recent studies have suggested a possible role for ADAMTS-1 during ovulation in rats (BOR 62:1090, 2000) and mRNAs for multiple ADAMTS subtypes have been detected in bovine preovulatory follicles (BOR 69:1506, 2003). In the present study, the temporal patterns of mRNA expression for four ADAMTS subtypes were investigated in theca interna during the bovine periovulatory period. PGF2 KEY WORDS: ovulation, ADAMTS, metalloproteinase, ovarian follicle |
was administered to Holstein heifers on Day 6 or 7 of the estrous cycle to induce luteal regression and a new follicular phase; the preovulatory gonadotropin surge was then induced 36 h later via GnRH (0.1 mg) injection. Ovaries (n=3/time point) were removed by ovariectomy at 0, 6, 12, 18, or 24 hours post-GnRH (ovulation is expected approximately 29 h post-GnRH). Theca interna was isolated from dissected periovulatory follicles and RNA was extracted. Expression of mRNA for ADAMTS-1, 2, 7, and 9 was determined by semi-quantitative RT-PCR and expressed relative to levels of 18S rRNA in the same samples. Levels of mRNA for ADAMTS-7 were elevated 2.5-fold at 12 h post-GnRH (P < 0.05), but returned to control levels by 24 h post-GnRH. In contrast, expression of mRNA for ADAMTS-1, 2 and 9 was similar to 0 h levels at 6, 12 and 18 h post-GnRH. However, 4.5 to 20-fold higher levels of mRNA were observed at 24 h post-GnRH compared to earlier time points (P < 0.05-0.08). The results show that levels of ADAMTS mRNA in theca interna are up-regulated in response to the LH/FSH surge. Increased levels of mRNA for these proteases during the bovine periovulatory period suggest specific and potentially important roles for ADAMTS family members in follicular rupture and the accompanying tissue remodeling. Supported by the NIH (HD41592).