Dose-response effects of prostaglandin F2α on the rabbit oviduct: Reproductive endocrine influence and tachyphylaxis

The dose-response effect of PGF_2α on the perfused oviduct of estrous and ovariectomized rabbits was determined. The oviducts of ovariectomized rabbits were more sensitive to the contractile effects of PGF_2α than those of estrous rabbits. This was demonstrated by a significant difference in the slope of the dose-response curves and in the magnitude of the maximum responses between the two groups. Blood pressure responses (depressor) to PGF_2α were not affected by the reproductive hormonal status of the rabbits. The oviduct (estrous rabbits) developed tachyphylaxis to the effect of PGF_2α. It was concluded that the response of the rabbit oviduct to PGF_2α is dependent on the reproductive hormone status of the animal and that the oviduct becomes insensitive to the effects of PGF_2α with repeated administration.