VARIABLES AFFECTING THE BIOLOGICAL ASSAY OF ESTROGENS

Abstract

A standard is necessary in the assay of estrone in oil since the position of the dosage response curve shifted within and between groups of rats. The slope of the curve was constant within and between groups of rats using the same smearing and inj. methods. The slope of the dosage response curve was significantly increased and limits of error of an assay significantly decreased by increasing the number of injs. from 1-6 equally divided injs. Preliminary priming, interpriming and different methods of assembling rats for subsequent inj. did not significantly influence the slope of the dosage response curve. The RD50 of rats injected at fortnightly intervals was within the same range as rats receiving the 1st inj. while rats injected at weekly intervals showed a definitely lower RD50. Within limits, the amt. of oil administered at each inj. was without a definite influence on the slope of the dosage response curve or RD50 and the response to estrone did not appear to be related to body wt. Using the same inj. treatment the slope of the dosage response curve for estradiol mono-benzoate was approx. the same as that found for estrone. Using 2 equally divided injs. the composite slope of the regression line for estrone utilizing 5000 rats was 6.00 with a standard error of 0.231 and the composite slope for 4 equally divided injs. using 2500 rats was 8.25 with a standard error of 0.340.