Expression of aquaporins 7 and 8 in the developing rat testis

Aquaporin (AQP) is a molecule that facilitates water permeability through c ell membranes and is widely distributed in the mammalian body. Among member s of the AQP family, AQP7 and AQP8 are predominantly expressed in the testi s. This paper examined the expression of these two AQPs in the developing r at testis, using northern blot and immunohistochemistry to visualize their roles during the progression of spermatogenesis in the developing testis. I n adult rats, expression of AQP7 was localized to spermatids, whereas AQP8 protein was observed in spermatocytes. In the developing testis, transcript s of AQP7 became detectable between 23 and 25 days post-partum, when round spermatids have been reported to appear. On the other hand, AQP8 mRNA was f irst detected between 13 and 16 days pout-partum, consistent with the repor ted first appearance of spermatocytes (13-14 days). AQP7 and AQP8 proteins were detectable at 28 days post-partum. The results suggest that AQP7 and A QP8 appear in the testis in accordance with the maturation of germ cells, a nd are involved in spermatogenesis.