Effect of insulin and epinephrine on some early oestrogenic responses in the rat uterus.

Oestradiol induces uterine eosinophilia and oedema, both in the intact immature rat and in the adult ovariectomized rat. These responses are decreased in ovariectomized-adrenalectomized adult rats, in adrenalectomized immature rats and in medullectomized immature rats. Pre-treatment with L-epinephrine restored both oestrogenic effects. Insulin inhibits oestrogen binding by uterine eosinophils and concurrently decreases oestrogen-induced uterine oedema and eosinophilia. These phenomena do not occur with inactive insulin. Insulin also induces blood eosinopaenia, suggesting an explanation for the findings in the uterus.