THE MAMMARY GLANDS OF SENILE NULLIPAROUS AND MULTIPAROUS RATS

Abstract

SUMMARY Sixty-nine nulliparous rats aged 607–1156 days and forty-six multiparous rats aged 614–1071 days were examined. The incidence of mammary tumours, hyperplasia of the mammary glands, enlargement of the pituitary, and occurrence of excessively large corpora lutea, were strikingly higher in the virgin than in the breeding animals. The nulliparae also tended to be heavier, and to possess larger ovaries and adrenal glands than did the parous animals.