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Testosterone influences renal electrolyte excretion in SHR/y and WKY males

DOI: 10.1186/1472-6793-8-5

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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.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.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.Human [1,2] and animal studies [3] have implicated Y-chromosome (Yc) loci as influencing the onset of male hypertension. In the Spontaneously Hypertensive Rat strain (SHR), the SHR Yc contains a locus which increases blood pressure (BP) approximately 20 mmHg compared to the normotensive Wistar Kyoto (WKY) Y chromosome. The Yc is only one genetic component of the total SHR hypertension. In SHR males, the presences of testosterone and androgen receptors through puberty are required for development of the hypertension and associated sympathetic nervous system potentiation, including the Yc component [4,5]. In examining phenotypes that mapped to the Yc and differed between SHR and WKY, our laboratory demonstrated an earlier rise of testosterone (T) levels in SHR males leading into puberty [4] and this phenotype mapped to the SHR Yc. Because of the unique biology of the mammalian Yc the blood pressure phenotype and the T timing phenotype cannot be separated usin


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