Males were introduced into the cages of six young female rats, which had been injected with 500γ testosterone propionate daily for 8 days.

Oestrus was delayed by from 6 to 12 days and was followed by recurrent pseudo-pregnancies or pregnancy. The young were sexually normal and sex-ratio was not significantly affected.

The injections caused vaginal mucification, which disappeared within 6 days.

These animals (and six controls) were killed on the 60th day when it was found that:

(1) There was no abnormal increase in body weight or in the mammary glands. The ovaries appeared normal.

(2) There was hypertrophy of the preputial glands and clitoris-like organ.

(3) The uteri of two animals that had been recurrently pseudopregnant, but not pregnant, had the typical plicated progestational appearance of testosterone propionate activation.

It is suggested that the delay in conception in all cases was due to the condition of the uterus, which underwent a cycle of pseudopregnancies (possibly initiated by the injections) in the presence of the male, until this cycle was terminated by pregnancy.

It is also suggested that the treatment temporarily removes the control of cyclical changes in the accessory organs from the ovary, which may itself retain an undisturbed cycle.

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