Prostaglandin F receptor expression in intrauterine tissues of pregnant rats
The stable metabolite of prostaglandin F2α, 15 keto-13, 14-dihydroprostaglandin F2α (PGFM), was measured from peripheral blood samples collected at specified intervals postpartum from 7 normal dairy cows and 4 cows with apparent endometritis. Plasma PFGM levels were significantly (P<.05) elevated for the first 5 days postpartum in the cows with endometritis (ranging from 4.0 to 5.0 ng/ml) compared to the controls (approximately 1.0 ng/ml). Beyond 5 days postpartum, plasma PGFM levels were not significantly different and decreased to approximately 0.4 ng/ml by day 13 in both groups. Time to uterine involution was not different between groups (less than 30 days). Therefore, uterine infections in cows during the puerperium was associated with elevated circulating PGFM levels. These findings and the observation that PGF2α is not uterotonic in the puerperal cow do not suggest a therapeutic use of PGF2α in order to evacuate the uterus.