SLC9A1 and Infertility: However, normal sperm motility is maintained in Nhe1-null mice, suggesting that Nhe1 gene is male fertility independent.12 Testis histology, sperm numbers and morphology are normal, but sNhe null males are completely infertile with severely diminished sperm motility.10 Further study suggests that cyclic AMP (cAMP) metabolism is impaired in spermatozoa lacking sNHE.13 A recent study showed that NHE8 is highly expressed in the Leydig cells and male mice lacking Nhe8 gene are infertile through its effect on modifying luteinizing hormone receptor (LHR) function.14