Progesterone-binding components of chick oviduct. I. Preliminary characterization of cytoplasmic components.

摘要: Abstract Induction of the synthesis specific protein avidin by a single administration progesterone has been demonstrated previously in chicks vivo and tissue minces monolayer cultures chick oviduct. To investigate mechanism induction, macromolecular components oviduct cytoplasm which bind 3H-progesterone vitro were isolated characterized sucrose gradient centrifugation, polyacrylamide gel electrophoresis, enzymatic digestion, filtration on Agarose (Bio-Rad Laboratories, Richmond, California). The radioactive steroid complex was identified as progesterone, not metabolite, paper chromatography. interaction with an apparent dissociation constant kd ≃ 8 x 10-10 m 0.3 KCl at 1° is reversed mild heating unlabeled g testosterone 20α-hydroxy-4-pregnene-3-one 17β-estradiol cortisol estrone androstenedione. participation steroid-binding site inferred from destruction 10-3 p-hydroxymercuribenzoate Pronase, but ribo- or deoxyribonucleases. number size cytoplasmic binding vary concentration technique isolation detection. In absence KCl, major are sedimentation coefficients, s020,w, about 5 S S, molecular weights 1.0 3.6 105 (estimated variation electrophoretic mobility concentration), sufficiently large effective radii to be eluted in, near, void volume columns A-0.5m. Under same conditions corticosteroid-binding globulin (CBG) plasma behaves component s020,w 3.7 mol wt 6.0 104. solutions containing CBG all sediment rate may distinguished each other distribution coefficients From latter results, Stokes 55 63 A can calculated for components, compared 37 CBG. progesterone-binding thus distinguishable physicochemical methods tested. functional role these induction supported (a) parallel order effectiveness various steroids competing potency inducers, (b) analogous effects treating diethylstilbestrol activity induction.