Hormonal Control of Lactation
The problems involved in the hormonal control of lactation are extremely complex, and researches now in progress, while adding to our knowledge of the factors at work, have not led to the postulation of any all-embracing or coherent theory. Ample evidence for this statement is given in the comprehensive review by Folley,' to whose work we referred in a leading article on lactation in July of last year. At the moment the chief interest in this country is focused on the actions of oestrogens and pituitary fractions and their relations. It is by now well established that mammary development may be incited in most mammals by combined treatment with an oestrogen and progesterone. In general, oestrogens appear to stimulate duct development and progesterone appears to be responsible for alveolar growth. There is no clear-cut evidence that these actions are direct, for experiments in hypophysectomized animals. have given conflicting results in the hands of different workers. In this connexion Speert2 performed an interesting experiment by painting the left nipples of immature male monkeys with an alcoholic solution of oestrone, the right nipples being painted with alcohol alone. He found that the oestronetreated mammae enlarged while the control right nipples were uiaffected, which goes to show that the pituitary was not involved. This conclusion, however, at present applies only to the mammary glands of the immature male monkey, because one of the most confusing factors in research on lactation has been the quite different results obtained by similar procedures in different species and in the different sexes of the same species. The technique of unilateral inunction does, however, provide a method for testing the direct action of hormones absorbed through the skin without removing the animal's own glands, which inevitably results in undesirable and usually uncontrollable secondary effects. Turning to the question of the secretion of milk by the mammary glands when they are fully developed, the pituitary is found to be accepted as the most important factor at work. It is perhaps unfortunate that the early researches of Riddle showed that anterior pituitary extracts which initiate lactation in a variety of species would also cause the growth of crop-glands in the pigeon. This was made the basis of an assay method for preparations and was almost universally adopted. It is only lately that it has been appreciated that this method of assay has distinct disadvantages. It is now realized that an extract capable of stimulating the pigeon's crop-gland does not necessarily initiate milk secretion in mammals. The commercial preparations of prolactin at present available are usually standardized by the crop-gland response, a fact which may accouint for conflicting clinical reports. Folley' therefore proposes that the name " prolactin " should be confined to crop-stimulating activity, and Folley and Young3 suggest the term " galactopoietic factor " for the anterior pituitary fraction responsible for increasing the milk yield of an animal already producing milk. " Lactogenic " is applied to the initiation of lactation in hypophysectomized animals. Folley and Young in their experiments showed that injections of crude anterior pituitary extracts increase the milk yield in cows in declining lactation to a greater extent than do purer preparations containing seven times as much prolactin (crop-stimulating) activity. This leaves open the question whether prolactin is galactopoietic, but proves that there is a distinct galactopoietic factor in the pituitary apart from a prolactin, or a principle which, acting with prolactin, has a synergistic galactopoietic effect. The present difficulty
An Ovarian Hormone: Preliminary Report on Its Localization, Extraction and Partial Purification, and Action in Test Animals
The fact that double ovariectomy abolishes the cyclic changes which normally occur in the genital tract of female mammals demonstrates that these changes are due to some influence from the ovaries. That this influence is hormonal in nature is indicated by the maintenance of cyclic changes by autotransplantation of the ovaries to other sites in the body. 1 Many attempts have been made to localize the seat of production of an internal secretion in definite ovarian structures. The follicles, the corpora lutea 2 developing in them after ovulation, and the interstitial tissue 3 have all been cited as possible sources, and many different ovarian preparations have been used clinically in the belief that therapeutic effects were being secured from accompanying hormones. But there appears to be no conclusive evidence of either a definite localization of the hypothetic hormone or of the specific effect claimed for the commercial ovarian extracts in
AN APPRAISAL OF OVARIAN THERAPY.
An appraisal of ovarian therapy, or of any other subject, must of necessity be tinctured with the personal element of the appraiser, so that it represents merely the point of view of an individual, based on such knowledge of facts as he may happen to possess. It presents more difficulty than does a mere survey of the literature, from which it differs to the same degree that the critique of a book differs from a mere synopsis of the book's contents. An accurate evaluation of such an undeveloped branch of therapeutics as that which forms the subject of this paper presupposes a finer judicial sense than the present writer can lay claim to. It is not easy to steer safely and sanely between the Scylla of over-enthusiasm and the Charybdis of undue skepticism. I may anticipate somewhat by saying that, of the two, Scylla looks much more dangerous to me than does Charybdis,