Prostaglandin F in the fallopian tube secretion of the ewe.

Oviducal secretions were obtained from conscious unrestrained ewes throughout the oestrous cycle via indwelling cannulae and the content of prostaglandin F (PGF) was determined by radioimmunoassay. Levels of PGF of up to 230 ng/ml were found in oviducal fluids obtained from ewes showing regular patterns of secretion and normal cyclical ovarian function as indicated by plasma progesterone measurement. Relatively large day to day fluctuations in content were evident, but there was no consistent relationship between concentration and stage of the oestrous cycle. Concentrations of PGF in excess of 100 ng/ml were common in preparations where autopsy later revealed infection or tissue irritation, and the concentration of PGF invariably exceeded 75 ng/ml when the concentration of protein in the oviducal fluid was abnormally high.