Relative Ability of Various Steroid Hormones to Promote Growth in Oviducts of Immature Ring-doves *

Edgar Allen1 was the first to point out and to emphasize the fact that estrogens are primarily "growth-promoting" agents. This characteristic of the estrogens is nowhere observed to better advantage than in the oviducts of birds. In the species of dove (Streptopelia risoria) utilized in the present study estrogens are evidently chiefly responsible for an increase in oviducal weight from about 20 mg. to 450 mg. in adults in reproductive rest, and to nearly 4500 mg. at each recurring period of ovulation (Riddle13 and unpublished data). Thus, one here observes a 220-fold increase in oviducal weight in a bird whose body weight remains essentially constant. Many investigators have reported that a number of the steroid hormones, not primarily estrogenic, possess some estrogenic potency. Clarke and Selye2 recently showed that, when tested on immature spayed rats, most or all of the hormonally active steroids possess one or another degree of estrogenic (folliculoid) activity. A growthpromoting action of certain estrogens or androgens (or both) on the avian oviduct has been reported for the ring-dove (Riddle and Tange18), fowl (Juhn and Gustavson5, Herrick4), English sparrow (Keck,6 Ringoen7 18, Pfeiffer and Kirschbaum11, Pfeiffer" ), spayed night-heron (Noble and Wurm9), starling (Witschi and Fugo2%), sparrow-hawk (Nelson and Stabler8), and canary (Porto and Scavone"2). Witschi20 has made a preliminary report on the minimal dose of some of the more generally used estrogens and androgens which, in 10 daily injections, will produce measurable enlargement of the oviducts of castrated sparrows and starlings. These several studies have demonstrated the sensitivity of the oviducts of immature or spayed birds (or of mature birds in reproductive rest) to injections of estrogenic hormones; and slight effects of testosterone and androsterone have been observed. The present study, started in 1937, is an attempt to utilize the undeveloped thread-like oviducts of young ring-doves for the simultaneous study of three questions: (a) The relative estrogenic (folli-