New concepts on the action of oestrogens in the uterus and the role of the eosinophil receptor system.
Two receptor systems for oestrogens have been demonstrated in the uterus: the cytosol-nuclear receptor system and the eosinophil receptor system. It has been proposed that the cytosol-nuclear receptor system mediates the genomic response to oestrogens in the uterus, while the eosinophil receptor system is thought to mediate the uterine edema and other early oestrogenic responses in the uterus. Cortisol is known to decrease drastically the number of eosinophils in the blood and therefore to limit their availability for migration to the uterus. The present results show that cortisol also drastically reduces both the oestrogen-induced uterine eosinophilia and the uterine wet weight responses, but does not interfere with the oestrogen-induced uterine RNA and protein increases. Oestradiol-17 beta has a higher affinity than oestriol for the cytosol-nuclear receptors and is now found to be the more potent oestrogen in inducing the genomic activation in the uterus. Estriol has a higher affinity than oestradiol-17 beta for the eosinophil receptors, and therefore, oestriol is the stronger oestrogen in inducing those oestrogenic effects which are mediated by the eosinophil receptor system. We conclude that the eosinophil receptor system for oestrogens is a new system, independent of Jensen's cytosol-nuclear receptor system, and this eosinophil receptor system is involved in the mechanism of oestrogen action in the uterus.
D000818:Animals; D002467:Cell Nucleus / Q000378:metabolism; D003600:Cytosol / Q000378:metabolism; D004247:DNA / Q000378:metabolism; D004804:Eosinophils / Q000378:metabolism*; D004958:Estradiol / Q000494:pharmacology; D004967:Estrogens / Q000494:pharmacology*; D005260:Female; D006003:Glycogen / Q000378:metabolism; D006854:Hydrocortisone / Q000494:pharmacology; D009929:Organ Size / Q000187:drug effects; D011506:Proteins / Q000378:metabolism; D012313:RNA / Q000378:metabolism; D051381:Rats; D011956:Receptors, Cell Surface; D014599:Uterus / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism
D004967:Estrogens; D011506:Proteins; D011956:Receptors, Cell Surface; D004958:Estradiol; D012313:RNA; D006003:Glycogen; D004247:DNA; D006854:Hydrocortisone