Enhancement of prostacyclin synthesis at the beginning of formation of caprine corpora lutea.
We examined changes in the levels of prostacyclin (PGI2) synthase mRNA and 6-keto-PGF1alpha, a stable metabolite of PGI2, in the caprine corpus luteum (CL) during its development and subsequent maintenance. We also looked at the effects of a potent GnRH antagonist (GA), which is known to suppress the release of luteinizing hormone (LH), on the PGI2 synthase mRNA level and the 6-keto-PGF1alpha content during CL development. Goats were divided into a control group (n=12) and a GA-treated group (n=6). They were treated with saline or GA (50 microg/kg, s.c.) on days 0 (day of ovulation), 4, and 8 (control only), and the CL were collected from a subset of goats (n=3 for each day) on days 0 (no saline), 4, 8, or 14 (control only). Ribonuclease protection assay was performed to quantify the mRNA in the CL using specific cRNA probes generated by RT-PCR and in vitro transcription. The 6-keto-PGF1alpha content in the CL was measured by radioimmunoassay. The level of PGI2 synthase mRNA and the 6-keto-PGF1alpha content in the CL in the control group decreased from day 0 to day 4 (P<0.01), and did not change thereafter from day 4 to day 14. Levels of PGI2 synthase mRNA and 6-keto-PGF1alpha content in the CL on days 4 and 8 were not affected by treatment with GA. These results suggest that PGI2 synthesis is regulated upward at the beginning of caprine CL formation; this may play a role in initiating CL development. This study also suggests that changes of PGI2 synthesis during CL development are probably not regulated by LH.
Kawate
Noritoshi
N
Laboratory of Theriogenology, Graduate School of Agriculture and Biological Sciences, Osaka Prefecture University, Sakai, Osaka, Japan. nkawate@vet.osakafu-u.ac.jp
Tsuji
Makoto
M
Tamada
Hiromichi
H
Inaba
Toshio
T
Sawada
Tsutomu
T
D015121:6-Ketoprostaglandin F1 alpha / Q000378:metabolism; D000818:Animals; D003338:Corpus Luteum / Q000378:metabolism*; D003577:Cytochrome P-450 Enzyme System / Q000096:biosynthesis / Q000235:genetics; D011464:Epoprostenol / Q000378:metabolism*; D005260:Female; D005786:Gene Expression Regulation / Q000502:physiology; D006041:Goats / Q000378:metabolism*; D007987:Gonadotropin-Releasing Hormone / Q000037:antagonists & inhibitors; D019746:Intramolecular Oxidoreductases / Q000096:biosynthesis / Q000235:genetics; D007986:Luteinizing Hormone / Q000378:metabolism; D008969:Molecular Sequence Data; D009928:Organ Specificity; D012333:RNA, Messenger / Q000378:metabolism
D012333:RNA, Messenger; D007987:Gonadotropin-Releasing Hormone; D015121:6-Ketoprostaglandin F1 alpha; D007986:Luteinizing Hormone; D003577:Cytochrome P-450 Enzyme System; D011464:Epoprostenol; D019746:Intramolecular Oxidoreductases; C022461:prostacyclin synthetase