Aquaporin 1 expression in the testis, epididymis and vas deferens of postnatal ICR mice

Aquaporin 1 (AQP1) is one of the water channels involved in water transfer and reabsorption. The results of a reverse transcription-polymerase chain reaction (RT-PCR) indicated that the level of AQP1 mRNA was increased in the testis and vas deferens, but decreased in the epididymis from the early postnatal period through puberty to adulthood. The results of Western blot analyses largely matched the RT-PCR findings for AQP1. AQP1 was immunohistochemically localized on the plasma membrane in the epithelia of rete testis and vas deferens at postnatal day 70, although it was hardly detectable at postnatal day 15. Nevertheless, AQP1 was expressed in the epithelia of the efferent duct and the initial segment of caput epididymis at postnatal day 15 and persisted into adulthood. The results taken together suggest that the expression and localization of AQP1 in mouse testis, epididymis and vas deferens are a stage-, tissue- and region-specific pattern and provide obvious clues that a possible relationship exists between the functional application of AQP1 for water reabsorption, and male reproduction and maturation.