Some newer aspects of reproductive physiology

Abstract

This paper deals with several problems in the field of reproductive physiology, chosen because of their newness and their importance, and because they indicate new trends in this field. The most outstanding advance of the past few years is the recent work on the chemistry of the male and female gonadal hormones (estrin, progestin, androkinin), indicating as it does the close chemical kinship of all three. Furthermore, a similarly close relation has been demonstrated between these hormones and certain well-known chemical substances of the sterol group, as well as the bile acids, certain vitamins, and certain carcinogenic substances. This last named relationship has sent investigators off full cry on a new scent, and it is even possible that the cancer problem may be unlocked with an endocrine key.While hitherto reproductive physiology has been concerned almost entirely with endocrinology, investigators are beginning to go beyond the endocrine glands in explaining certain cyclical phenomena, and to speak of a sex center located somewhere in the midbrain. Certain cyclical disturbances of menstruation would seem to justify such an assumption and to suggest also a possible participation of the posterior lobe. One of the most interesting phenomena coming under this head is the weight increase and edema seen in many women at menstruation, and in exaggerated form in the so-called generalized edema of menstruation. This type of cyclical water balance disturbance may be seen even in the absence of a bleeding cycle. Its exact mechanism is not known, but its occurrence seems in some way linked up with a change in the globulin-albumin proportions of the blood serum.Reference is made again to the undoubted possibility that periodic bleeding, clinically interpreted by the patient as normal menstruation, may occur without ovulation. The bearing of this on the study of sterility is obvious, for it undoubtedly explains some cases. The technic which we have found most satisfactory in determining whether or not a patient is ovulating is briefly described.Finally, brief reference is made to recent investigations suggesting that menstrual bleeding is due to withdrawal of progestin rather than of estrin, as has been generally accepted. Because of the now well-established chemical relation between estrin and progestin, and the fact that they exert a similar inhibiting effect upon the hypophysis, there is no material change in the general concept of the mechanism responsible for the bleeding of menstruation.