Angulo C, Rauch M C, Droppelmann A, Reyes A M, Slebe J C, Delgado-López F, Guaiquil V H, Vera J C, Concha I I
Instituto de Bioquímica, Facultad de Ciencias, Universidad Austral de Chile, Valdivia.
J Cell Biochem. 1998 Nov 1;71(2):189-203.
We analyzed the expression of hexose transporters in human testis and in human, rat, and bull spermatozoa and studied the uptake of hexoses and vitamin C in bull spermatozoa. Immunocytochemical and reverse transcription-polymerase chain reaction analyses demonstrated that adult human testis expressed the hexose transporters GLUT1, GLUT2, GLUT3, GLUT4, and GLUT5. Immunoblotting experiments demonstrated the presence of proteins of about 50-70 kD reactive with anti-GLUT1, GLUT2, GLUT3, and GLUT5 in membranes prepared from human spermatozoa, but no proteins reactive with GLUT4 antibodies were detected. Immunolocalization experiments confirmed the presence of GLUT1, GLUT2, GLUT3, GLUT5, and low levels of GLUT4 in human, rat, and bull spermatozoa. Each transporter isoform showed a typical subcellular localization in the head and the sperm tail. In the tail, GLUT3 and GLUT5 were present at the level of the middle piece in the three species examined, GLUT1 was present in the principal piece, and the localization of GLUT2 differed according of the species examined. Bull spermatozoa transported deoxyglucose, fructose, and the oxidized form of vitamin C, dehydroascorbic acid. Transport of deoxyglucose and dehydroascorbic acid was inhibited by cytochalasin B, indicating the direct participation of facilitative hexose transporters in the transport of both substrates by bull spermatozoa. Transport of fructose was not affected by cytochalasin B, which is consistent for an important role for GLUT5 in the transport of fructose in these cells. The data show that human, rat, and bull spermatozoa express several hexose transporter isoforms that allow for the efficient uptake of glucose, fructose, and dehydroascorbic acid by these cells.
我们分析了己糖转运蛋白在人类睾丸以及人类、大鼠和公牛精子中的表达情况，并研究了公牛精子对己糖和维生素C的摄取。免疫细胞化学和逆转录-聚合酶链反应分析表明，成年人类睾丸表达己糖转运蛋白GLUT1、GLUT2、GLUT3、GLUT4和GLUT5。免疫印迹实验表明，在从人类精子制备的膜中存在与抗GLUT1、GLUT2、GLUT3和GLUT5反应的约50 - 70 kD的蛋白质，但未检测到与GLUT4抗体反应的蛋白质。免疫定位实验证实了GLUT1、GLUT2、GLUT3、GLUT5以及人类、大鼠和公牛精子中低水平的GLUT4的存在。每种转运蛋白异构体在头部和精子尾部均显示出典型的亚细胞定位。在尾部，GLUT3和GLUT5在所检测的三种物种的中段水平存在，GLUT1存在于主段，而GLUT2的定位因所检测的物种而异。公牛精子转运脱氧葡萄糖、果糖以及维生素C的氧化形式脱氢抗坏血酸。细胞松弛素B抑制了脱氧葡萄糖和脱氢抗坏血酸的转运，表明促进性己糖转运蛋白直接参与了公牛精子对这两种底物的转运。果糖的转运不受细胞松弛素B的影响，这与GLUT5在这些细胞中果糖转运中的重要作用一致。数据表明，人类、大鼠和公牛精子表达几种己糖转运蛋白异构体，这些异构体使这些细胞能够有效摄取葡萄糖、果糖和脱氢抗坏血酸。
