The glucose transport facilitator GLUT8 is predominantly associated with the acrosomal region of mature spermatozoa

The glucose transporter 8 (GLUTS) is a recently identified member of the family of sugar transport facilitators. In human tissues GLUTS is predominantly expressed in testis in a gonadotropin-dependent manner. It is shown here that the onset of mRNA synthesis of GLUT8 during the maturation of mouse testis coincides with the appearance of mature spermatozoa. Furthermore, immunohistochemistry with antiserum against the C-terminus of GLUTS indicated that the protein was associated with spermatozoa within the seminiferous and the epididymal tubules. The GLUTS immunoreactivity was detected within the head of mouse and human spermatozoa in the acrosomal region, and appeared to be located at the plasma membrane as well as within the cells. This specific expression and localization of GLUTS suggests that the transport facilitator plays a major role in the fuel supply of mature spermatozoa, and that it is a potential target for inhibition of sperm cell function.