Changes in prostaglandin F concentration in the uterus (shell gland) of the hen oviduct in relation to oviposition and estrogen.

The prostaglandin F (PGF) concentration of the uterus (shell gland) of the hen oviduct, measured by a radioimmunoassay, was found to increase slightly 6 h before oviposition and steeply immediately after oviposition. An intravenous injection of arginine vasotocin (AVT) caused the increase in the uterine PGF concentration and induced oviposition. When indomethacin was injected before the injection of AVT, the uterine PGF concentration was not increased, and the incidence of oviposition was reduced. Estrogen injection caused an increase in the uterine PGF concentration at 1 and 2 h after injection. Specific binding of the estrogen receptor of the uterine tissue increased 9 and 7 h before oviposition. The slight increase in the uterine PGF concentration 6 h before oviposition may be due to the action of estrogen via its receptor, and the steep increase immediately after oviposition may be caused by AVT released at the time of oviposition.