The Antigonadotropic Factor. Reversibility of the Prolan-Antiprolan Effect

In order to explain the mechanism of the antigonadotropic function we thought it necessary to examine the following questions: Is prolan irrevocably destroyed by antiprolan or is the process reversible? While investigating the chemical properties 1 of antiprolan we found that prolan and antiprolan differ from each other as follows: Prolan is more sensitive to HCl than antiprolan but less sensitive to NaOH. n/10 up to n/15 HCl destroys prolan, but not antiprolan; n/10 up to n/15 NaOH destroys antiprolan, but not prolan. If the prolan-antiprolan effect is reversible it must be possible to destroy antiprolan by means of NaOH and thereby to release the prolan and render it biologically active once more. By using HCl we should be in a position to destroy the prolan, to liberate the antiprolan once more and to render it capable of again inactivating freshly added prolan. If the process is irreversible the prolan-antiprolan-complex cannot be changed in any way whatsoever either by NaOH or by HCl.

The following experiments make it evident that the prolan-antiprolan effect is reversible.

The reactivation experiments can be divided into two groups. I. Reactivation of the prolan out of the prolan-antiprolan complex by selective destruction of the antiprolan by means of NaOH. II Reactivation of the antiprolan out of the prolan-antiprolan complex by selective destruction of prolan by means of HCl.

I. Reactivation of Prolan. Thirty mg. of antiprolan-acetonedry powder (corresponding to 30 PAU∗) was dissolved in 1.2 cc. of aqua dest. 0.8 cc. = 20 PAU of this solution was mixed with 20 RU of prolan (dissolved in 0.4 cc. aqua dest.). This neutral prolan-antiprolan mixture (= 1.2 cc.) was now divided into 2 parts (0.6 cc. each) with which Experiments 1 and 2 were carried out.