Auto-Amplification System for Prostaglandin F2α in Bovine Corpus Luteum

The bovine corpus luteum (CL) is hypothesized to utilize a local auto-amplification system for prostaglandin (PG) F2 alpha production. The objective of the present study was to determine if such a PGF2 alpha auto-amplification systemexists in the bovine CL, and if so, which factors regulate it. PGF2 alpha significantly stimulated intra-luteal PGF2 alpha production in all luteal phases, but did not affect PGE2 production. The stimulatory effect of exogenous PGF2 alpha on CL PGF2 alpha production was lower at the early luteal phase. Indomethacin, an inhibitor of prostaglandin-endoperoxide synthase (PTGS), significantly suppressed the PGF2 alpha-stimulated PGF2 alpha production by luteal tissue, indicating that the PGF2 alpha in the medium was of luteal origin. Consistent with these secreted-PGF2 alpha profiles, PGF2 alpha receptor (PTGFR) protein expression was higher during the mid and late luteal phases than at early and developing luteal phases. Treatment of cultured bovine luteal cells obtained from the mid-luteal phase with PGF2 alpha (1 mu M) significantly increased the expressions of PTGS2, PGF synthase (PGFS), and carbonyl reductase1 (CBR1) at 24 hr post-treatment. Together, these results suggest the presence of a local auto-amplification system for PGF2 alpha mediated by PTGS2, PGFS, and CBR1 in the bovine CL, which may play an important role in luteolysis. (C) 2014 Wiley Periodicals, Inc.