Guinea Pig Copulatory Reflex in Response to Aqueous Extracts of Adrenal Cortex

Abstract

It has been demonstrated that progesterone 1 , 2 and desoxycorticosterone 3 will elicit the copulatory reflex in the spayed guinea pig after preliminary estrogen treatment but that certain androgens will not do so. 4

We thought it of interest to determine whether aqueous extracts of the adrenal cortex which contain the life-maintaining principle would produce this reaction.

The method used to test the cortical extracts was similar to that described by other workers. 4 Two groups of guinea pigs, A and B, consisting of 60 and 11 animals respectively, were used. The results obtained from administering graded doses of the extract on successive weeks are shown in Table I.

It will be seen that there is a relation between the dose administered and the number of animals showing the copulatory reflex. The data on the small group are included since the response to each dose agrees so closely with that of the larger group. Furthermore, group B was given each dose of the extract one week prior to the administration of the corresponding dose to group A. Since these figures were tabulated, 30 animals representing one-half of group A have given a 50% response to a dose of 1 cc. This result offers further evidence of the reliability of the method.

The extract used in obtaining the data shown in the table contained 2.9 rat units 5 per cc. Other preparations which contained more than 2.9 rat units proved to be more active in producing the copulatory reflex. These preliminary findings indicate that there is a correlation between the life-maintaining and the copulatory-reflex activity of adrenal cortical extracts. It seems probable, therefore, that this reaction in the guinea pig might be used as a method for assaying such preparations.