Bovine cytosol androgen receptor (ARC) concentrations were examined simultaneously in various regions of the uterus and in ovarian tissues of cows, and were related to cytosol estrogen (ERC) and progesterone receptor (PRC) concentrations and circulating steroid levels. ERC concentrations were 3-7-fold and PRC concentrations 13-29-fold those of ARC in bovine endometrial and myometrial tissues. When serum progesterone levels were low, both endometrial and myometrial ARC, endometrial ERC, and endometrial and myometrial PRC concentrations were higher (p < 0.05) than those observed during higher progesterone concentrations. Because serum 5 alpha-dihydrotestosterone (5 alpha-DHT) concentrations were higher during the luteal phase, it is possible that ARC was down-regulated by this natural ligand at this phase of the cycle. There were no differences between uterine horns in endometrial or myometrial ARC concentrations. Bovine cervical and ovarian stromal tissue also contained ARC, and the concentrations were about the same as in the endometrium and the myometrium. The relative binding affinities (RBAs) of some steroid hormones towards ARC in vitro were: the synthetic compound R1881 (146%), 5 alpha-dihydrotestosterone (100%), testosterone (75%) while estradiol-17 beta, progesterone and dexamethasone had lower RBAs (2, < 1, < 1% respectively). Cytosol androgen receptor concentrations correlated significantly with cytosol progesterone (PRC) and estrogen receptor (ERC) concentrations, both in the endometrium and myometrium. These data show that androgens, such as 5 alpha-DHT, may participate the endocrine regulation of bovine reproductive tissues.
Koncentrationerna av cytoplasmiska androgen receptorer (ARC) i kornas livmoder och ovarier studerades samtidigt med estrogen (ERC) och progesteronreceptorer (PRC) och jämfördes med steroid hormoner i blodserum. Koncentrationerna av ERC var 3–7 och PRC 13–29 gånger högre än motsvarande ARC koncentrationer både i endometrium och myometrium. Koncentrationerna av cytoplasmiska ARC i de undersökta kornas livmödrer varierade enligt brunstcykeln. Då progesteronhalten i blodserum var låg, var även 5α-dihydrotestosteronhalten (5α-DHT) låg - livmoderns ARC-koncentrationer i endometrium och myometrium var däremot på en högre nivå. Också ERC koncentrationerna i endometrium och PRC både i endometrium och myometrium var högre under denna period. Vid höjda serum progesteron och 5α-DHT koncentrationer minskade emellertid livmoderns ARC-halt samtidigt med ERC och PRC koncentrationerna. Antagligen berodde minskningen av ARC på att höjda 5α-DHT-koncentrationer verkade hämmande på ARC-nivån. ARC koncentrationerna i olika delar av livmodern befanns vara på samma nivå. En positiv korrelation mellan mängderna av androgen-, progesteron- och estrogenreceptorer i livmodern kunde påvisas. Syntetisk metyltrienolon (R1881) hade en högre och testosteron en mindre affinitet till ARC an 5α-DHT in vitro. Estradiol-17β, progesteron och dexametason hade endast en minimal affinitet till ARC.