Open AccessProgesterone Receptors in the Chick Oviduct.
Author(s) -
MESTER Jan,
BAULIEU EtienneEmile
Publication year - 1977
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1977.tb11265.x
Subject(s) - oviduct , cytosol , progesterone receptor , receptor , medicine , endocrinology , biology , cell nucleus , nuclear receptor , chemistry , cytoplasm , estrogen receptor , biochemistry , enzyme , cancer , breast cancer , gene , transcription factor
1 Exchange techniques were developed for measurement of total progesterone receptor binding sites concentration in the cytosol and nuclei of chicken oviduct. 2 The level of progesterone receptor in the cytosol was under both oestrogen and progesterone control. Primary stimulation by oestradiol benzoate increased the receptor concentration from approximately 10000 sites/cell to approximately 40000 sites/cell in the magnum cytosol; subsequent withdrawal from oestrogen treatment led to a decrease to approximately 14000 sites/cell after 6 weeks. After progesterone administration (3 mg/kg) to oestrogen‐stimulated, withdrawn chicken, the receptor concentration decreased to approximately 40% of the initial level within the first 4 h; afterwards the receptor level rose again and by 40 h exceeded slightly the initial one. 3 The nuclear levels of the receptor reached a maximum at 1 h after the progesterone injection; however, the gain of the binding sites by the nuclei (∼ 900/nucleus) did not account for their loss from the cytosol. The maximum nuclear receptor level was not influenced by the dose of progesterone within range of 1‐10 mg/kg. 4 The extractibility of the nuclear progesterone receptor by 0.5 M NaCl was strongly influenced by preincubation of the nuclei at 30 C; irrespective of this preincubation, approximately 12% of the nuclear receptor resisted extraction with 2 M NaCl/5 M urea.