New Developments in Ovarian Dynamics and the Law of Follicular Constancy

Abstract

ABSTRACT It has been shown in previous papers in this Journal (1, 2) that very characteristic phenomena take place in an ovarian fragment if the total ovarian mass is reduced by partial castration. There is an hypertrophy of the ovarian fragment and a greatly reduced number of young ova, while large follicles and often follicular cysts are found in the fragment. The diminution of the number of primary follicles was explained by assuming that they had been absorbed during follicular development. These conclusions, together with those of Arai, Hammond and Asdell in mammals, of Hartman in the opossum, of Pearl and Schoppe in the fowl, were summarised in “the law of follicular constancy,” which means that the number of ova entering into follicular development, the rhythm of follicular development and the degree which is attained by follicular development are constant and are controlled by somatic factors outside the ovary. The latter supposition was a further development of the theories of Heape, Sand (3), Hammond and Marshall (4). In further experiments on cats (2) it was shown that the diminution of the number of young ova in an ovarian fragment and the formation of follicular cysts do not depend upon the operative interference itself, as there is no diminution of young ova and there are no follicular cysts in ovarian fragments when the total ovarian mass is not diminished. Later, further experimental evidence (5) concerning the law of follicular constancy was obtained by grafting a third ovary into normal guinea-pigs. No corpus luteum was ever found in such ovarian grafts when examined several months later, though corpora lutea are always present in ovarian grafts in previously castrated females.