Comparative immunolocalization of GLUTs 1, 2, 3 and 5 in boar, stallion and dog spermatozoa.

Spermatozoa, as other eukaryotic cells, need hexoses to produce energy to maintain membrane homeostasis, to move along the female genital tract and to carry the male genome to the female gamete. GLUTs are a family of proteins that permit and improve the passive transport of hexoses inside cells. This study was aimed at investigating the presence and localization of GLUTs 1, 2, 3 and 5 in boar, stallion and dog spermatozoa by both immunofluorescence and western blotting. GLUTs exhibited a peculiar distribution along the sperm cell depending on the isoforms considered, the hexose they transport and the different species. The localization of GLUTs after capacitation and acrosome reaction highlighted the possible changes in their distribution because of the different functional moment. Only in dog spermatozoa changes in GLUTs distribution were demonstrated; these changes could be related to the different metabolic needs and modifications occurring in the sperm cell.