Testosterone changes bladder and kidney structure in juvenile male rats.

Testosterone affects male development, maturation and aging but limited data exist on testosterone effects on the juvenile genitourinary system. We hypothesized that testosterone has bladder and kidney developmental effects, and investigated this in juvenile male rats. To examine the testosterone effect 21-day-old prepubertal male Wistar rats were divided into 3 groups of 12 each, including sham orchiectomy as controls, and bilateral orchiectomy with vehicle and bilateral orchiectomy with testosterone. Starting at age 28 days (week 0) testosterone enanthate (5 mg/100 gm) or vehicle was injected weekly. Testosterone was measured at study week 0 before injection, and at weeks 1, 6 and 16. Whole bladders and kidneys were evaluated for androgen receptor, bladder collagen-to-smooth muscle ratio, and renal morphometry and immunohistochemistry. Testosterone was not detectable at week 0 in all groups. It remained undetectable at weeks 1, 6 and 16 in the orchiectomy plus vehicle group. Testosterone levels were physiological in controls and rats with orchiectomy plus testosterone but levels were higher in the latter than in the former group. Rats with orchiectomy plus testosterone had increased bladder-to-body and kidney-to-body weight ratios (p<0.01 and <0.05, respectively), and decreased collagen-to-smooth muscle ratio than the orchiectomy plus vehicle and control groups. Rats with orchiectomy plus testosterone had a lower renal total glomerular count (p<0.01) but increased androgen receptor density. In juvenile male rats testosterone was associated with increased bladder and renal mass, and increased bladder smooth muscle. Testosterone associated kidneys also appeared to have fewer but larger glomeruli. These data support an important role for sex hormones in structural and functional development of the bladder and kidney.