The formation of nodular hyperplasia of the suprarenal cortex and the development of mammary tumors in dba mice ovariectomized at birth have been reported by us in a short paper (1). Since then further data have been secured which enable us to follow the suprarenal changes from their earliest manifestation to the fully formed abnormalities and correlate these with the changes taking place in the vagina, uterus, and mammary glands.The observations are based on data collected from 95 dba female mice which were ovariectomized at birth and killed at different ages. This particular strain has about 50 per cent breast tumor incidence in the virgin females.
MethodThe ovariectomy was performed on the first post partum day. The mice w e r e anesthetized by chilling. They were placed on a sheet of paper in the freezing compartment of an electric refrigerator for about 7 minutes. Small dorsal incisions were made and each ovary, together with its capsule and part of the oviduct, was removed. A dissecting microscope was used to aid in locating these organs. Each incision was closed by one stitch taken with fine white silk thread. The mice survived the operation well, and their mothers readily accepted and continued to take care of them.At the autopsy of every animal a careful search was made to ascertain whether any ovarian regeneration had taken place. All suspicious areas were sectioned but in no case was ovarian regeneration found.
Changes in the Suprarenal GlandIn all the castrated animals killed after 3 to 4 months of age the suprarenals show characteristic changes which progressively lead to the formation of nodular hyperplasia. Most of the glands were studied on serial sections.The earliest changes consist of the hypertrophy of a few cells of the zona *
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