Prostaglandin (PG)F-2a:PGE ratio increased (P < 0.05) from day 4 to 13-14 of cycle. PGF (AKR1B1) & PGE (mPGES-1) Synthases were increased (P < 0.05) on day 13 (vs day 7). Tumor necrosis factor (TNF)-a increased (P < 0.05) mPGES-1, but not AKR1B1 mRNAs. TNF-a had no significant effects on AKR1B1 or mPGES-1 protein abundance. TNF-a significantly increased PGE-2 but had no effect on PGF-2a or PGF-2a:PGE-2 ratio.