Evidence for separate binding sites for progesterone and RU486 in the chick oviduct
| Autor: | Manjul K. Agarwal, Naomi Eliezer, Virinder K. Moudgil, Cliff Hurd, Giuseppina Lombardo |
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| Rok vydání: | 1986 |
| Předmět: |
endocrine system
medicine.medical_specialty Hot Temperature animal structures medicine.medical_treatment Uterus Oviducts Biology Promegestone Steroid chemistry.chemical_compound Cytosol Internal medicine Centrifugation Density Gradient polycyclic compounds medicine Animals Estrenes Binding site Molecular Biology Progesterone urogenital system Cell Biology Mifepristone Ligand (biochemistry) Endocrinology medicine.anatomical_structure chemistry Oviduct Female Receptors Progesterone Chickens hormones hormone substitutes and hormone antagonists medicine.drug |
| Zdroj: | Biochimica et Biophysica Acta (BBA) - Molecular Cell Research. 889:192-199 |
| ISSN: | 0167-4889 |
| DOI: | 10.1016/0167-4889(86)90104-7 |
| Popis: | Binding characteristics of synthetic steroid, mifepristone (RU38486 - also referred to as RU486), were examined in cytosol prepared from the chick oviduct and the calf uterus, and were compared with those of progesterone and synthetic progestin R5020. Unlike [3H]progesterone binding, the [3H]RU486 binding in the oviduct cytosol did not saturate at 50 nM ligand concentration. The [3H]progesterone binding could not be eliminated in the presence of excess RU486, and [3H]RU486 binding was seen to be indisplaceable upon pretreatment of the chick oviduct cytosol with a 1000-fold excess progesterone. It is apparent that the chick oviduct cytosol is endowed with two separate sets of sites which interact with progesterone and RU486 independently. Furthermore, [3H]RU486 binding in the chick oviduct cytosol remained intact when incubated for 60 min at 37 degrees C; it exhibited a single ionic form upon elution from DEAE-Sephacel and the [3H]RU486-associated radioactivity sedimented in the 4 S region both in salt-free and 0.3 M KCl-containing 5-20% sucrose gradients. In the calf uterus cytosol, both steroids exhibited comparable binding profiles. Our results provide evidence that chick oviduct possesses distinct binding sites that accept either progesterone or RU486, but not both, as is the case in the calf uterus. |
| Databáze: | OpenAIRE |
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