Neonatal estrogenization of the male mouse results in urethral dysfunction

Purpose: Analysis of voiding pattern, urodynamic measurements and immunohistochemical methods were performed in order to evaluate the effects of neonatal estrogenization on voiding functions of adult male mice. Materials and Methods: Metabolic cages were used for recording the voiding volumes and frequencies. Bladder pressure and mean flow during voiding were measured in transvesical cystometry. Location of estrogen receptors and organization of smooth muscles in lower urinary track were demonstrated using immunohistochemical staining. Results: Neonatally estrogenized (neoDES) male mice had lower voided urine volumes (the average voided urine volume and average of the three largest volumes) and higher voiding frequencies than control mice. In transvesical cystometry, the maximum bladder pressure during the high-frequency oscillation phase of voiding was significantly elevated. The average urinary flow rate was decreased. Conclusions: Urodynamically, these findings are consistent with the concept that neonatally estrogenized mice have infravesical obstruction. The predominance of estrogen receptors in the periurethral region and changes in urethral smooth muscle cells immunocytochemically stained with alpha-actin-antibody support the concept of urethral wall musculature as a target of estrogen action.