{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,9]],"date-time":"2026-07-09T16:12:48Z","timestamp":1783613568256,"version":"3.55.0"},"reference-count":0,"publisher":"Bioscientifica","issue":"1","content-domain":{"domain":["journals.bioscientifica.com"],"crossmark-restriction":true},"short-container-title":[],"published-print":{"date-parts":[[1978,1,1]]},"abstract":"<jats:title>SUMMARY<\/jats:title>\n                  <jats:p>The synthetic progestogen R5020 (17,21-dimethyl-19-norpregna-4,9-diene-3,20-dione) binds with high affinity (Ka = 8\u00b78 \u00d7 108 1\/mol at 0 \u00b0C) to the progesterone receptor from rat uterine cytosol. At nanomolar concentrations, equilibrium is attained in less than 90 min. R5020 has a very low affinity for other specific steroid-binding proteins (corticosteroid-binding globulin and oestrogen receptors) present in relatively high concentrations in the uterine cytosol. The affinity of the receptor for the natural hormone progesterone is remarkably low (Ka= 1 \u00d7 108\u22121\u00b77 \u00d7 1081\/mol at 0 \u00b0C) which explains the instability of progesterone\u2013receptor complexes. Advantage may be taken of this property to remove endogenous progesterone easily by charcoal treatment at 0 \u00b0C, a treatment which does not modify the concentration of receptors. A method based on these characteristics is described for the assay of the total number (progesterone-bound and unbound) of receptor sites in uterine cytosol. This assay may be used in various physiological situations where endogenous progesterone is present at unknown concentrations.<\/jats:p>","DOI":"10.1677\/joe.0.0760021","type":"journal-article","created":{"date-parts":[[2008,12,11]],"date-time":"2008-12-11T17:22:29Z","timestamp":1229016149000},"page":"21-31","update-policy":"https:\/\/doi.org\/10.1530\/crossmarkpolicy-5","source":"Crossref","is-referenced-by-count":35,"title":["CHARACTERIZATION AND ASSAY OF THE PROGESTERONE RECEPTOR IN RAT UTERINE CYTOSOL"],"prefix":"10.1530","volume":"76","author":[{"given":"M. T.","family":"VU HAI","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"E.","family":"MILGROM","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"416","container-title":["Journal of Endocrinology"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/joe.bioscientifica.com\/view\/journals\/joe\/76\/1\/joe_76_1_004.xml","content-type":"text\/html","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/journals.bioscientifica.com\/joe\/article-pdf\/76\/1\/21\/133324\/joe_76_1_004.pdf","content-type":"application\/pdf","content-version":"vor","intended-application":"syndication"},{"URL":"https:\/\/journals.bioscientifica.com\/joe\/article-pdf\/76\/1\/21\/133324\/joe_76_1_004.pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,7,9]],"date-time":"2026-07-09T15:13:33Z","timestamp":1783610013000},"score":1,"resource":{"primary":{"URL":"https:\/\/journals.bioscientifica.com\/joe\/article\/76\/1\/21\/23705\/CHARACTERIZATION-AND-ASSAY-OF-THE-PROGESTERONE"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[1978,1,1]]},"references-count":0,"journal-issue":{"issue":"1","published-print":{"date-parts":[[1978,1,1]]}},"URL":"https:\/\/doi.org\/10.1677\/joe.0.0760021","relation":{},"ISSN":["1479-6805","0022-0795"],"issn-type":[{"value":"1479-6805","type":"electronic"},{"value":"0022-0795","type":"print"}],"subject":[],"published":{"date-parts":[[1978,1,1]]}}}