Gender hormones and the progression of experimental polycystic kidney disease.
BACKGROUND
Male gender is a risk factor for progression of autosomal-dominant polycystic kidney disease (ADPKD), clinically and in the Han:SPRD rat model. Orchiectomy limits progression, but mechanisms of the detrimental effect of androgen, and/or beneficial effects of estrogen, are not known. This protocol tested the hypothesis that male gender (intact androgen status) promotes progression, while female gender (intact estrogen status) is protective; and that these disease-modifying effects are due to changes in expression of known fibrotic mediators.


METHODS
Studies were performed in male and female noncystic control (+/+) and cystic (+/-) rats subjected to orchiectomy, ovariectomy, or sham operation. At 12 weeks of age, renal function was measured. Blood and kidneys were taken for measurement of plasma and renal renin, endothelin (ET-1), endothelial nitric oxide synthase (eNOS), and vascular endothelial growth factor (VEGF), using biochemical, protein expression, and immunohistochemical methods.


RESULTS
Cystic male rats exhibited significantly reduced glomerular filtration (GFR) and effective renal plasma flow (ERPF) rates, with suppression of plasma and renal renin, up-regulation of renal ET-1 and eNOS, and down-regulation of renal VEGF expression. Orchiectomy attenuated the fall in GFR and ERPF, while numerically limiting changes in eNOS and VEGF. Female rats exhibited less cystic growth, with normal renin status, lesser elevation of renal ET-1, and proportionately lesser changes in VEGF and eNOS. Ovariectomy led to higher blood pressure and reduced GFR and ERPF, with a trend toward upregulation of ET-1, and significant down-regulation of VEGF and eNOS.


CONCLUSIONS
Female gender is protective, but ovariectomy attenuates the protective effect of female gender, in association with changes in renal expression of ET-1, VEGF, and eNOS. The accelerated disease in male rats can be attenuated by orchiectomy and consequent changes in expression of disease mediators.
Stringer
Kenneth D
KD
Division of Nephrology and Hypertension, Oregon Health and Science University, Portland, Oregon 97239, USA.
Komers
Radko
R
Osman
Shukri A
SA
Oyama
Terry T
TT
Lindsley
Jessie N
JN
Anderson
Sharon
S
D000728:Androgens / Q000502:physiology*; D000818:Animals; D001835:Body Weight; D019332:Endothelin-1 / Q000378:metabolism; D004967:Estrogens / Q000502:physiology*; D005260:Female; D005355:Fibrosis; D007668:Kidney / Q000378:metabolism / Q000473:pathology; D008297:Male; D009569:Nitric Oxide / Q000378:metabolism; D052250:Nitric Oxide Synthase Type III / Q000378:metabolism; D009919:Orchiectomy; D009929:Organ Size; D010052:Ovariectomy; D016891:Polycystic Kidney, Autosomal Dominant / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology*; D051381:Rats; D011922:Rats, Mutant Strains; D017207:Rats, Sprague-Dawley; D012084:Renin-Angiotensin System / Q000502:physiology; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism
D000728:Androgens; D019332:Endothelin-1; D004967:Estrogens; D042461:Vascular Endothelial Growth Factor A; D009569:Nitric Oxide; D052250:Nitric Oxide Synthase Type III