Growth Processes Induced by Estrogenic Hormones

In former investigations we have studied the growth processes which take place in the mammary gland ( 1 j and in the vagina and cervix ( 2 ) of mice under the 'influence of estrogenic hormones, and the conditions under which these .processes become cancerous. The investigations recorded here extend this analysis to the uterus of the mouse. By uterus, we understand that part of the vaginal-cervical-uterine tract which begins approximately at the point of bifurcation. In earlier studies on the guinea-pig, it was pointed out (3) that the cervix may be divided into three parts: a vaginal, an intermediate, and a uterine part. The condition is similar in the mouse, although in this animal the division is perhaps not quite so definite as in the guinea-pig. Also there exists in the mouse a transition zone between cervix proper and uterus, in which the tissue has essentially the structure of the uterus but still retains some cervical characteristics, namely, a somewhat greater tendency to the production of low squamous epithelium than is present in the uterus proper. Thus there may be found here an area in which are uterine glands covered by low squamous rather than by cylindrical epithelium; furthermore, there may develop in this area glandular cysts which are filled with hyaline nucleated cells instead of with a diffuse gelatinous material, such as is usually encountered in uterine cysts. In this transition zone the cysts may be lined entirely or partially with a low squamous epithelium. In accordance with the characteristics of the epithelium of the cervix and vagina and its tendency to assume the squamous-cell type, we find in these areas a greater incidence of precancerous and cancerous changes. In the uterus, on the other hand, as the experiments to be reported in this paper prove, the tendency to produce precancerous or cancerous changes is much less. The uterus and other sex organs were studied in 501 mice, this number including 177 control mice which were not subjected to treatment with sex hormones. The strains used and the ages at which the various groups were autopsied were as follows ( I signifies an age of one to eleven months; 11, twelve to seventeen months; 111, eighteen months and over, and IIIa, twenty months and over) : ( A ) Control Mice