title: Ovarian-independent fluctuations of estradiol receptor levels in mammalian tissues.
abstract: Three types of periodic fluctuation in tissue concentrations of estradiol receptor protein have been observed. A seasonal variation is described in the uteri of 12-16-week-old calves and of ovariectomized pigs, and in mammary tumor tissue obtained from postmenopausal women. A circadian rhythm has been demonstrated in uteri of ovariectomized rats. An irregular periodic fluctuation has been found in uteri of ovariectomized and of ovariectomized/hypophysectomized rats, with the period varying from 9 to 15 days. These observations establish that a substantial turnover of receptor occurs in the absence of hormone and that 'normal' baseline values of receptor concentration do not exist.
mesh_terms: D000818:Animals; D001943:Breast Neoplasms / Q000378:metabolism; D002369:Castration; D002417:Cattle; D002940:Circadian Rhythm; D004958:Estradiol / Q000378:metabolism*; D005260:Female; D006801:Humans; D007016:Hypophysectomy; D008593:Menopause; D010053:Ovary / Q000502:physiology*; D051381:Rats; D011960:Receptors, Estrogen / Q000378:metabolism*; D012621:Seasons; D013045:Species Specificity; D013552:Swine; D014599:Uterus / Q000378:metabolism*
chemical_list: D011960:Receptors, Estrogen; D004958:Estradiol