UNTERSUCHUNGEN ÜBER DIE ZENTRALE AKTIVITÄT DES OESTRIOL. EIN WIRKUNGSVERGLEICH ZUM 17β-OESTRADIOL BEI NEUGEBORENEN RATTEN
ABSTRACT In order to clarify the central effect of oestriol quantitatively 5 day old male and female rats were treated with one subcutaneous injection of oestriol or 17β-oestradiol. From the 60th day of life these animals were mated with proven fertile partners. The animals were considered sterile if no pregnancy occurred within 60 days of the observation period. With reference to the standard 17β-oestradiol an activity was found for oestriol of 0.125 when tested on male rats and an activity of 0.26 when tested on female rats. Male animals treated with 17β-oestradiol were twice as sensitive as female rats. In female and male rats oestriol caused an identical central stimulation. The central effect of oestriol in relation to the standard 17β-oestradiol was found to be much lower than former investigation had shown. Hence this effect especially with only one injection must be due to the more rapid elimination of oestriol as compared with the standard 17β-oestradiol.