Activity of synthetic estrogens on oral administration in the domestic fowl and turkey

JAAP AND THAYER (1944) reported that the dimethyl ether of diethylstilbestrol was a much more active estrogen for oral administration in the domestic fowl than diethylstilbestrol, its diethyl ether or its dipropionate. This result was in distinct contrast to that observed in rats and mice (Sondern, Sealey and Kartsonis, 1941), where the oral activity appeared to decrease with increase in the length o£ the chain in the alkoxy groups. Due to the practical significance of estrogens in the fattening of poultry (Jaap and Thompson, 1945; Thayer, Jaap, and Penquite, 1945), it appeared desirable to expilore the oral activity of a number of synthetic compounds known to have some estrogenic activity in mammals. The relative quantity of an estrogenic substance required to produce estrus in the rat and mouse varies with the compound.