Abstract
The demonstration that the follicular hormone from ovaries of swine would satisfactorily substitute for the hormonal function of the ovaries of non-pregnant rats and mice 1 , 2 has led us to attempt its extraction from other sources. So far we have obtained it from large, normal follicles of ovaries of swine, cattle, and sheep and from cystic follicles of swine and man, and have injected it into mice, rats, guinea pigs, rabbits, monkeys and human patients. These experiments seem sufficient to establish the expectation that this active substance is not species specific at least among mammals.
After trials in several laboratory mammals we have come to the conclusion that the rat, with both ovaries removed, is the best test animal. It has the following advantages: (1) the time required for the growth reaction of the tissues of the genital tract to the growth stimulus of the injected hormone is short, 36 to 48 hours, thus returning a decisive test after a few injections of a small amount of extract; and (2) the course of the experiment can be followed accurately by microscopic examination of the cell content of the vaginal smear, thus making it possible to use a test animal repeatedly.
As shown in our earlier work, the hormone is present in liquor folliculi from which all cells have been removed. The conclusion drawn was that it is secreted by the follicle cells under the influence of the ovum as the dynamic center. 2 Theoretically, it should be produced in the ovaries of all animals in which there is cyclic growth in the genital tract while the ova are ripening. Our first tests of material from hens were of extracts made by Dr. Doisy of fresh eggs from the market.
Get full access to this article
View all access options for this article.