Prostaglandin F2 alpha metabolites in plasma and urine during pseudopregnancy in the rabbit.

Two prostaglandin (PG) F2 alpha metabolites, 13,14-dihydro-15-keto PGF2 alpha (dhkPGF2 alpha) in blood and 5 alpha, 7 alpha-dihydroxy-11-keto tetranorprostane 1,16-dioic acid (PGF2 alpha UM) in urine, were measured in the pseudopregnant rabbit by radioimmunoassay. During pseudopregnancy, marked increases in the two PGF2 alpha metabolites were demonstrated at about the time of luteal regression. Hysterectomy and intrauterine administration of indomethacin prolonged the life span of corpora lutea in the pseudopregnant rabbit by 8 and 5 days, respectively, with no elevation of PGF2 alpha UM excretion. The findings indicate that PGF2 alpha is a uterine luteolysin in the pseudopregnant rabbit, as in other animal species.