Abstract
1. Oxytocin in daily doses of 0.4 and 2.0 I. U. was injected intraperitoneally for 8 to 14 days into mature virgin rats. Their estrous cycle was not influenced at all by this treatment.
2. Oxytocin in a dose of 2.0 I. U. was injected singly at the stage of proestrus or estrus, or repeatedly starting at the stage of proestrus or estrus for 8 days. During the course of oxytocin treatment, silk threads were placed in the uterine horns of the animals. The injured parts of the uteri occasionally showed slight swelling, which could be regarded as a simple reaction to foreign substances. Deciduoma formation was not observed histologically.
3. In histological sections no differences could be noticed between the ovaries and mammary glands of oxytocin-treated rats and those of saline injected controls. Normal cyclic changes of the uteri were observed in the oxytocin injected rats as well as in the controls.
From these results it was inferred that oxytocin may have no effect in stimulating the release of prolactin from the anterior pituitary gland, at least in mature virgin rats.
