Fluid regulation within the male gonad is an important process for promoting sperm
differentiation and maturation. Aquaporins (AQPs) are a family of thirteen integral
membrane proteins involved in these processes. The expression of several genes of
AQPs occurs in the male reproductive tract of humans and other animal species, although
there are few studies on domestic animals. In this study, the localization of AQP7,
AQP8, and AQP9 as well as the abundances of protein and mRNA transcripts were examined
in normal and cryptorchid dog testes. There was immunohistochemical localization of
AQP7, AQP8, and AQP9 in both the tubular and interstitial compartments of the normal
and retained testes and crytorchid dogs, albeit there was an obvious difference in
cellular localization with the testes from the cryptorchid dogs. These results were
supported by western blotting and real-time RT-PCR analyses, there was a lesser AQP7
and greater AQP9 abundance of protein and mRNA transcripts in the cryptorchid testis.
These findings indicate combined testicular functions of AQPs in cell volume regulation.
In addition, with the cryptorchid condition characterized there was a different cellular
distribution of AQPs supporting the thought that early detection is important for
controlling possible side effects of cyptorchidism, such as pre-neoplastic and carcinogenic