Testosterone influences renal electrolyte excretion in SHR/y and WKY males.
BACKGROUND
The Y-chromosome (Yc) and testosterone (T) increase blood pressure and may also influence renal electrolyte excretion. Therefore, the goal of this study was to determine if the Yc combined with T manipulation could influence renal Na and K excretion.


METHODS
To investigate the role of the Yc and T, consomic borderline hypertensive (SHR/y) and normotensive Wistar-Kyoto (WKY) rat strains were used (15 weeks) in three T treatment groups: castrate, castrate with T implant and gonadally intact males. Urine was collected (24 hrs at 15 weeks of age) for Na and K measurements by flame photometry. RT-PCR was used to demonstrate the presence of renal androgen receptor (AR) transcripts. Plasma T and aldosterone were measured by RIA. In another experiment the androgen receptor was blocked using flutamide in the diet.


RESULTS
Na and K excretion were decreased by T in SHR/y and WKY. AR transcripts were identified in SHR/y and WKY kidneys. Plasma aldosterone was decreased in the presence of T. Blockade of the AR resulted in a significant increase in Na excretion but not in K excretion in both SHR/y and WKY males.


CONCLUSIONS
T influences electrolyte excretion through an androgen receptor dependent mechanism. There was not a differential Yc involvement in electrolyte excretion between WKY and SHR/y males.
Toot
Jonathan
J
Biology Department, The University of Akron, Akron, OH 44325-3908, USA. jtoot@hotmail.com
Jenkins
Cathy
C
Dunphy
Gail
G
Boehme
Shannon
S
Hart
Mike
M
Milsted
Amy
A
Turner
Monte
M
Ely
Daniel
D
D000818:Animals; D006973:Hypertension / Q000378:metabolism*; D007668:Kidney / Q000378:metabolism*; D008297:Male; D009919:Orchiectomy; D011188:Potassium / Q000652:urine*; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY; D011944:Receptors, Androgen / Q000378:metabolism*; D012964:Sodium / Q000652:urine*; D013739:Testosterone / Q000097:blood / Q000378:metabolism*; D014998:Y Chromosome
D011944:Receptors, Androgen; D013739:Testosterone; D012964:Sodium; D011188:Potassium