Homologous up-regulation of androgen receptor expression by androgen in vascular smooth muscle cells.
OBJECTIVE
Androgens play an important role in the arterial vascular system, and androgen receptors (AR) have been identified in vascular smooth muscle cells (VSMCs). This study examined the effects of testosterone exposure on AR gene expression in cultured rat aortic smooth muscle cells.


METHODS
Changes in AR protein and messenger RNA (mRNA) levels after androgen exposure were determined using immunoblotting and Northern blotting analysis respectively.


RESULTS
Treatment of synchronized VSMCs with testosterone increased both cytoplasmic and nuclear AR protein expression in a dose- and time-dependent fashion, whereas exposure of VSMCs to androgen for 10 min induced a transient down-regulation of AR protein. Meanwhile, AR mRNA level was also up-regulated, but to a much smaller extent. Pretreatment with transcription inhibitor and translation inhibitor repressed cytoplasmic AR protein levels to 46 and 12% (means) of the androgen treatment control level respectively. Furthermore, androgen up-regulation of intracellular AR protein was partially inhibited by androgen antagonist.


CONCLUSIONS
Androgen increases AR expression in VSMCs at the level of both transcription and non-transcription.
Ma
Rui
R
Department of Cardiology, Nanfang Hospital, Guangzhou, China.
Wu
Saizhu
S
Lin
Qishui
Q
D000818:Animals; D018931:Antineoplastic Agents, Hormonal / Q000494:pharmacology; D015152:Blotting, Northern; D015153:Blotting, Western; D002452:Cell Count; D002467:Cell Nucleus / Q000378:metabolism; D002478:Cells, Cultured; D003593:Cytoplasm / Q000378:metabolism; D005485:Flutamide / Q000494:pharmacology; D015870:Gene Expression / Q000187:drug effects; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000378:metabolism*; D014176:Protein Biosynthesis / Q000235:genetics; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D051381:Rats; D017207:Rats, Sprague-Dawley; D011944:Receptors, Androgen / Q000096:biosynthesis* / Q000235:genetics; D013739:Testosterone / Q000494:pharmacology; D013936:Thymidine / Q000378:metabolism; D014158:Transcription, Genetic / Q000235:genetics; D015854:Up-Regulation / Q000235:genetics*
D018931:Antineoplastic Agents, Hormonal; D012333:RNA, Messenger; D011944:Receptors, Androgen; D013739:Testosterone; D005485:Flutamide; D013936:Thymidine