Lack of Estrin Concentration I N Adenofibroma of the Mammary Gland I N Rats

Since the incidence and growth of adenofibroma of the mammary gland are known to be affected by the ovarian hormones, the observation oi Geschickter and Lewis (1-5) that this tumor may contain large amounts of estrogenic and gonadotropic hormones is of fundamental interest. They suggest that since adenofibroma is composed of the elements normally stimulated by estrin, namely the ducts and periductal connective tissue, the growth of the tumor may be secondary to an ability of a local area of the mammary gland to concentrate estrin within itself. If it could be established that in the tumor there are constantly present larger amounts of estrin than in the other tissues of the same individual, this would constitute a unique physiological phenomenon of great interest to students of neoplastic disease. Geschickter and Lewis are careful to point out that the variation in their results makes it impossible to draw any definite conclusions except that “ the hormones found (estrogenic and gonadotropic) are in all probability concerned in the physiology of the tumor.” Their values for estrin in human adenofibromas varied from 200 to 18,000 rat units per kilo, dry weight. Unfortunately, no normal tissues from the same individuals were assayed for control. However, assay of a normal premenstrual uterus revealed 3000 rat units of estrin per kilo, while normal breasts yielded 0-6000 rat units per kilo. A rat adenofibroma gave a level of 2000 rat units per kilo, while normal rat mammary tissue was stated to give a negative result. Since, however, the amount and source of the mammary tissue were not given, this comparison is without value. Doubt as to the presence of actual concentration of hormone in these tumors was voiced by Frank et al. ( 6 ) , who found similar amounts of estrin in normal uterus and psoas muscle (800-8000 rat units per kilo). No confirmation of Geschickter and Lewis’ findings has yet appeared except for the finding by Heiman and Krehbiel ( 7 ) of 1 rat unit per gram fresh weight of a rat adenofibroma. The latter authors, however, did not assay control tissue, though they assumed that the level of estrin in the body was not excessive since the estrous cycle was normal. The present investigation deals with an attempt to determine the level of estrin in rat adenofibroma as compared to that in striated muscle, both tissues being obtained in each instance from the same individual. Striated muscle was chosen as the control tissue since it is, in all probability, indifferent as far as concentration or destruction of the hormone is concerned, and it is available in larger amounts than any other tissue.