title: [Specific binding of 3H-progesterone to a plasma protein in the guinea pig fetus].
abstract: The presence of a protein that binds specifically and with high affinity to progesterone is found in the plasma of fetal guinea Pig. Progesterone and 5 alpha-dihydroxyprogesterone strongly compete for the 3H-progesterone-protein complex. 5 beta-dihydroxy progesterone, 20 beta-dihydroxyprogesterone, testosterone and synthetic progestagen, R-5020 (17,21-dimethyl-19-norpregna-4, 9-diene-3,20 dione), also compete but less intensely. 17-hydroxyprogesterone, aldosterone, cortisol, oestradiol and oestrone have no effect. The 3H-progesterone-protein, complex has an affinity of Kd = 8.8 +/- 3.5 x 10(-10) M and in sucrose density gradient the sedimentation coefficient is 4.6 S.
mesh_terms: D004092:20-alpha-Dihydroprogesterone / Q000097:blood; D000818:Animals; D001667:Binding, Competitive; D001798:Blood Proteins / Q000378:metabolism*; D005260:Female; D005333:Fetus / Q000378:metabolism; D006168:Guinea Pigs; D011247:Pregnancy; D011374:Progesterone / Q000097:blood*; D011485:Protein Binding
chemical_list: D001798:Blood Proteins; D004092:20-alpha-Dihydroprogesterone; D011374:Progesterone
vernacular_title: Liaison spécifique de la 3H-progestérone à une protéine du plasma du foetus de cobaye.