The functional correlation between the ovaries, uterus, and mammary glands in the rabbit, with observations on the œstrous cycle

Recent experimental work has resulted in proving that there is a definite functional correlation between the growth of the corpora lutea in the ovaries and the hypertrophy of the mammary glands (Ancel and Bouin and O’Donoghue). In the present paper experiments are described showing that this hypertrophy in rabbits that have never been pregnant may be so considerable as to lead to the production of milk, the secretion of which may be temporarily increased by the injection of pituitary extract. Further experiments are recorded showing that the uterus is not a necessary factor in the development of the mammary gland. The influence of experimentally produced corpora lutea upon the uterus is also described. The Influence of the Ovaries upon the Mammary Glands. It is well known that the mammary glands in man begin to undergo enlargement at the time of puberty in correlation with the increase in ovarian activity. Apart from this pubertal growth which is more or less permanent, there is known frequently to be a slight swelling of the glands at each menstrual period. A similar process takes place in the sow and probably in other mammals at the “ heat ” periods (Marshall). In the virgin rabbit we have noticed a growth of the mammary duets in six cases prior to ovulation, but the cell proliferation, though quite definite, did not extend to the glandular tissue. Experiments were undertaken to determine if the growth could be increased by injecting fœtus extract, with a view to bringing further evidence to hear upon the hypothesis, put forward by Starling and Lane-Claypon, that the anabolic changes involved in mammary hypertrophy are dependent upon a foetal hormone. The results, however, were negative in each case.