01470naa a2200277 a 450000100080000000500110000800800410001910000210006024501310008126000090021252007020022165000150092365000120093865000140095065000090096465000140097365000170098765000200100465000140102465000100103865300230104865300150107165300230108670000170110977300660112620706622017-06-09       1980    bl uuuu     u00u1 u    #d1 aMATHIESON, R. A.  aBinding of phyto-oestrogen and oestradiol-17 beta by cytoplasmic receptors in the pituitary gland and hypothalamus of the ewe.  c1980  aAbstract: The binding of the phyto-oestrogens, genistein and coumestrol by oestrogen receptors in pituitary and hypothalamic cytosol of the ewe was studied in relation to the binding of [3H]-oestradiol-17 beta. It was determined that the interaction of these compounds was competitive. The apparent dissociation constant for oestradiol-17 beta in ewe pituitary cytosol was determined to be 0 x 26 +/- 0 x 12 (S.E.M.) nmol/l. Apparent inhibition constants for coumestrol and genistein were determined to be 60 and 170 nmol/l respectively. These results suggested that phyto-oestrogens can interfere with the normal oestrogen feedback mechanisms with respect to release of gonadotrophine in the ewe.  acoumestrol  acytosol  aEstrogens  aEwes  aGenistein  aHypothalamus  aPituitary gland  areceptors  aSheep  aChemical Phenomena  aOestrogens  aReleasing hormones1 aKITTS, W. D.  tJournal of Endocrinologygv. 85, n. 2, p. 317-325, Apr. 1980.