Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
10891924 | Theriogenology | 2015 | 10 Pages |
Abstract
The aim of this study was to examine whether progesterone (P4) and its antagonists, onapristone (ZK299) and mifepristone (RU486), affect the levels of PGRA and PGRB messenger RNA (mRNA) and protein in the cow uterus which may be important in understanding whether the final physiological effect evoked by an antagonist depends on PGR isoform bound to the antagonist. Endometrial slices on Days 6 to 10 and 17 to 20 of the estrous cycle were treated for 6 or 24Â hours for mRNA and protein expression analysis, respectively, with P4, ZK299, or RU486 at a dose of 10â4, 10â5, or 10â6Â M. In the samples on Days 6 to 10 of the estrous cycle, PGRAB mRNA was stimulated by P4 (10â4Â M; PÂ <Â 0.01) and RU486 (10â6; PÂ <Â 0.001) and was decreased by ZK299 (10â5; PÂ <Â 0.05). In contrast, PGRB mRNA was decreased by the all P4 (PÂ <Â 0.01) and ZK299 (PÂ <Â 0.001) doses and by two of the RU486 doses (10â4Â M; PÂ <Â 0.01 and 10â5Â M; PÂ <Â 0.01). In samples on Days 17 to 20 of the estrous cycle, PGRAB mRNA was stimulated by RU486 (10â5Â M; PÂ <Â 0.001). PGRB mRNA was decreased by P4 (10â4 and 10â5Â M; PÂ <Â 0.001), ZK299 (10â4 and 10â5Â M; PÂ <Â 0.001), and RU486 (10â4Â M; PÂ <Â 0.01 and 10â6Â M; PÂ <Â 0.001) and was increased by ZK299 (10â6Â M; PÂ <Â 0.001) and RU486 (10â5Â M; PÂ <Â 0.001). In samples on Days 6 to 10 of the estrous cycle, PGRB protein levels were decreased (PÂ <Â 0.05) by all three ZK299 doses and by two of the RU486 doses (10â4Â M; PÂ <Â 0.05 and 10â5Â M; PÂ <Â 0.01). In contrast, in samples on Days 17 to 20, both PGRA and PGRB protein levels were decreased by ZK299 stimulation (10â5Â M; PÂ <Â 0.05 and 10â5Â M; PÂ <Â 0.01, respectively), whereas only PGRA protein levels were increased by RU486 (10â5Â M; PÂ <Â 0.01). Both ZK299 and RU486 may exhibit both agonist and antagonist properties depending on which receptor isoform they affect. As a result, an increase or decrease in the expression of a particular PGR isoform will be observed.
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Authors
Robert Rekawiecki, Magdalena K. Kowalik, Jan Kotwica,