Abstract
This paper is the first of a series in which the results of studies on estrogenic activity of herbage will be presented. Uterine weight responses of mice are commonly used as indices of estrogenic substances. But, sensibilities of these responses are ample in variation under different experimental conditions. The present paper deals with the experimental conditions for biological estimation of estrogenic activity. In the first experiment, immature female mice were used and uterine weight responses to oral-catheter injection of estrogenic substances were compared with those to oral administration of the same samples admixed with the basal diet. In the second experiment, estrogenic substances were admixed with the basal diet and uterine weight responses of ovariectomized mice were compared with those of intact immature mice. In the third experiment, dose response lines of estrogenic substances, i.e., diethylstilbestrol (DES), genistin and alfalfa, were examined. The results obtained are summarized as follows : 1. The uterine weight responses of the intact immature mice to estrogenic substances were not obvious in either case of oral-catheter injection and dietary administration. 2. The uterine weight of the overiectomized immature mice responded very much better than that of the intact mice to the dietary administration of estrogenic substances. Besides, the standard deviation of uterine weight of the ovariectomized mice was smaller than that of the intact mice. 3. Dose response lines of DES and genistin ran almost completely parallel with each other. And the estrogenic activity of genistin, which we prepared from soybean meal, was estimated at about 4×10^<-6> times of DES. 4. Dose response line of alfalfa-extract ran parallel to that of DES under the dosage of alfalfa 20g-extract/mouse/6 days. Over-dose of alfalfa-extract obstructed the uterine weight response and its dose response line ran unparallel to that of DES. This fact suggests that the estrogenic activity of alfalfa should be estimated on the basis of at least two different amount of dose.
