Time-course of the effects of nafoxidine and oestradiol on separate groups of responses in the uterus of the immature rat.

The effects of 0.05 or 15 micrograms oestradiol, and of 5 or 50 micrograms nafoxidine on the uterus of immature rats were investigated. Nafoxidine appeared at least as efficient as oestradiol for the action on RNA, protein and glycogen content but was less efficient for inducing early increase in wet weight and in eosinophil migration into the uterus. If eosinophil counts in the deep stroma were considered, a strong parallelism was revealed between this response and the increase in wet weight. These results represent a further argument for a dissociation between early and late effects of oestrogens and for the existence of separate sites of hormone action. They also lend support to the hypothesis of a mediation of wet weight response by eosinophils.