Expression of androgen receptor and androgen regulation of NDRG2 in the rat renal collecting duct.
Androgens are known to regulate gene expression in the renal proximal tubule. Whether the distal parts of the nephron, in particular the cortical collecting duct (CCD), where sodium reabsorption is controlled tightly by aldosterone, are also targets for these hormones is unknown. Real-time PCR on rat isolated renal tubules showed that androgen receptor mRNA is not only, as expected, expressed in the proximal tubule, but also in the CCD. We examined the effects of adrenalectomy (ADX) plus castration and in-vivo administration of the active metabolite of testosterone, dihydrotestosterone (DHT), on the intrarenal expression of N-myc downstream regulated gene 2 (NDRG2), an early aldosterone-induced gene located specifically in the CCD. NDRG2 belongs to a newly identified family of differentiation-related genes; although the function of these genes remains elusive, regulation of NDRG1 by androgens has been suggested. Castration plus ADX increased NDRG2 expression (RNase protection assay) significantly in the whole kidney, and a single i.p. injection of DHT caused a significant decrease in NDRG2 expression 4 h afterwards (up to 24 h). Furthermore, real-time PCR on microdissected tubules revealed that the decrease in NDRG2 expression caused by DHT is restricted to the CCD. Thus, aldosterone and androgens have opposite effects on NDRG2 expression in the renal CCD. These results are the first demonstration of androgen-dependent gene regulation in the rat renal CCD.
Boulkroun
Sheerazed
S
INSERM U478, Institut Federatif de Recherche 02, Universite Paris 7, Faculte de Medecine Xavier Bichat, 16 rue Henri Huchard, BP 416, 75870 Paris Cedex 18, France.
Le Moellic
Cathi
C
Blot-Chabaud
Marcel
M
Farman
Nicolette
N
Courtois-Coutry
Nathalie
N
D000315:Adrenalectomy; D000728:Androgens / Q000494:pharmacology*; D000818:Animals; D002369:Castration; D013196:Dihydrotestosterone / Q000494:pharmacology; D005786:Gene Expression Regulation / Q000187:drug effects; D007668:Kidney / Q000187:drug effects / Q000378:metabolism; D007684:Kidney Tubules / Q000187:drug effects / Q000378:metabolism; D007685:Kidney Tubules, Collecting / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D009419:Nerve Tissue Proteins / Q000235:genetics*; D011506:Proteins / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D011944:Receptors, Androgen / Q000235:genetics*
D000728:Androgens; C489395:Kap protein, rat; C507213:Ndrg2 protein, rat; D009419:Nerve Tissue Proteins; D011506:Proteins; D012333:RNA, Messenger; D011944:Receptors, Androgen; D013196:Dihydrotestosterone