Comparative Immunolocalization of GLUTs 1, 2, 3 and 5 in Boar, Stallion and Dog Spermatozoa

Abstract

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.

Current knowledge on boar sperm metabolism: Comparison with other mammalian species

“…Regarding mammalian sperm, the first striking question is that focused on the specific distribution of these GLUTs along the sperm cell membrane. Thus, whereas GLUT1 is distributed along the entire tail and acrosome in boar and stallion sperm, the same hexose transporter is mainly located in the apical area of the acrosome in dog and donkey sperm, in the acrosome, midpiece, and principal piece of the tail in human sperm, and, finally, in the apical and acrosomal area of the head and the principal piece and final piece of the tail in rat and bull sperm [31][32][33]. Similar differences are also observed in the distribution of the other GLUTs, the circumstance being striking that the studied species that showed greatest differences in their overall GLUTs distribution when compared with the other studied species is dogs [32].…”

Porcine sperm capacitation involves tyrosine phosphorylation and activation of aldose reductase

“…In pigs, Nichol et al (1992) reported that the concentrations of glucose were significantly lower in the whole oviduct (0.59 mM) than in the blood plasma (4.56 mM), but its concentration in the ampullary-isthmic junction during the preovulatory period (1.65 mM) was greater than during other periods of the estrous cycle. In boar sperm, the utilization of glucose is controlled in part by the heterogeneous localization of GLUT family transporters over the entire sperm surface (Bucci et al 2010). Sperm aldose reductase seems to be physiologically quiescent until sperm arrive in the cauda epididymis because the concentrations of the extracellular respiration substrates, glucose and fructose, are extremely low (Pruneda et al 2006).…”

Investigation of relationship between expression of the glucose transporter3 (GLUT3) and sperm quality in Asian elephants (Elephas maximus)

“…These GLUT3 proteins were localized at the principal and end piece of the sperm tail, with the exclusion of the middle piece. However, the localization was different from the sperm of other mammals; for example, in boar, positive GLUT3 was evident in the acrosome and in a band across the middle of the sperm head (5,6,19,20). In bull sperm, the positive GLUT3 signal was present only in the middle piece (8,19).…”