EFFECT OF INDUCED PYOMETRA ON LUTEAL LIFE-SPAN AND UTERINE FLUID CONCENTRATIONS OF PROSTAGLANDINS AND INTERFERONS IN COWS

The objective was to determine whether occurrence of persistent corpor a lutea in cows with pyometra could be explained by accumulation of pr ostaglandins and interferons in the uterus. Pyometra was induced by tr eatment with hCG, followed by intrauterine infusions of iodine and Act inomyces pyogenes. Five of the seven treated cows developed pyometra a s indicated by extended estrous cycles (30-37+ d) and presence of puru lent uterine exudate at slaughter (Day 37 after estrus). Mean (+ stand ard error) concentrations of prostaglandins E(2) and F-2 alpha for the cows with pyometra were 34.7 +/- 14.4 and 96.3 +/- 28 ng/ml, while th e concentrations in uterine flushings in the remaining 2 cows averaged 1.85 +/- 0.7 and 0.9 +/- 0.2 ng/ml, respectively. Based on Western bl otting, none of the cows had detectable concentrations of either inter feron-alpha or interferon-tau in uterine secretions. In conclusion, py ometra results in increased uterine prostaglandin secretion. While inc reased secretion of cytokines associated with bacterial infection may be contribute to this effect, there was no evidence in this study to s uggest that interferons are involved in the mechanism which causes per sistence of the corpus luteum in bovine pyometra.