Means of Augmenting the Ovarian Response to Gonadotropic Substances

Abstract

We presented evidence 1 that the serum of the pregnant mare contains 2 substances, one which produces sexual maturity and fully formed corpora lutea in the immature rat and another which is ineffective by itself but is capable of augmenting the response to pituitary synergist prepared after the method of Evans, et al. 2 We obtained augmentation of this synergist by the use of a fraction prepared from mare serum after the method described by Fevold et al. 3 for the preparation of luteinizer from the pituitary. Cole and Hart 4 obtained augmentation of this synergist by serum from non-pregnant mares. Evans 5 obtained augmentation of his synergist by combining it with sera from pregnant and non-pregnant individuals of various species. From evidence now at hand it appears that the augmentation produced by these sera or their extracts is due not to a specific gonadotropic substance but rather to their protein content. Similar augmentation can be produced by a wide variety of inert materials.

Augmentation by inert materials was first reported by Fevold 3 in the preparation of his follicle stimulator when he stated that precipitation of the active material on tannic acid and injection of the tannate in colloidal solution accentuates the ovarian response. Max-well 6 working with the hypophyseal gonadotropic substance, was able to obtain increased response by the addition of ZnSO₄ to the crude pituitary extract. We have been able to confirm Maxwell's work, obtaining an average increase of about 100% in ovarian weight by the addition of ZnSO₄ to the crude pituitary extract.∗ Furthermore using pituitary synergist (Evans'method) we have obtained a 3-fold increase in ovarian weight by the addition of ZnSO₄ and also significant increases by the addition of casein or egg albumin.