title: Comparative pharmacology of oestrogens and catechol oestrogens: actions on the immature rat uterus in vivo and in vitro.
abstract: The effects of primary and catechol oestrogens on the uterus of the immature rat were compared. Because differences between the in-vivo and in-vitro oestrogenic actions of catechol oestrogens on the secretion of LH had been observed, their effects on a peripheral target organ, the uterus, were examined under similar conditions. In-vivo effects were assessed by measurement of uterine weight, induction of uterine cytoplasmic progestogen receptors, and by histological examination. In-vitro actions were determined by measurement of oestrogen-specific induced protein. It was found that the uterotrophic effects in vivo of 4-hydroxyoestradiol were indistinguishable from those of oestradiol whereas 2-hydroxyoestradiol was only weakly oestrogenic and 2-hydroxyoestrone had no effect. However, in vitro, 2-hydroxyoestradiol was as effective as 4-hydroxyoestradiol or oestradiol in stimulating synthesis of uterine induced protein, and 2-hydroxyoestrone, although less potent than oestradiol, had a significant effect. These results were consistent with the observed effects on the secretion of LH. The differences between in-vivo and in-vitro uterotrophic properties of catechol oestrogens can be explained on the basis of known pharmacokinetic factors.
mesh_terms: D000818:Animals; D004958:Estradiol / Q000031:analogs & derivatives / Q000494:pharmacology; D004967:Estrogens / Q000494:pharmacology*; D002393:Estrogens, Catechol / Q000494:pharmacology*; D004970:Estrone / Q000494:pharmacology; D005260:Female; D006894:Hydroxyestrones / Q000494:pharmacology; D009929:Organ Size / Q000187:drug effects; D051381:Rats; D011919:Rats, Inbred Strains; D012741:Sexual Maturation; D014599:Uterus / Q000187:drug effects*
chemical_list: D004967:Estrogens; D002393:Estrogens, Catechol; D006894:Hydroxyestrones; D004970:Estrone; D004958:Estradiol; C001390:2-hydroxyestradiol; C014036:4-hydroxyestradiol; C024980:2-hydroxyestrone