The mammary gland increases energy requirements during pregnancy and lactation to support epithelial proliferation and milk nutrients synthesis. Lactose, the principal carbohydrate of the milk, is synthetized in the Golgi of mammary epithelial cells by lactose synthase from glucose and UPD galactose. We studied the temporal changes in the expression of GLUT1 and GLUT8 in mammary gland and their association with lactose synthesis and proliferation in BALB/c mice. Six groups were used: virgin, pregnant at 2 and 17 days, lactating at 2 and 10 days, and weaning at 2 days. Temporal expression of GLUT1 and GLUT8 transporters by qPCR, western blot and immunohistochemistry, and its association with lactalbumin, Ki67, and cytokeratin 18 within mammary tissue was studied, along with subcellular localization. GLUT1 and GLUT8 transporters increased their expression during mammary gland progression, reaching 20-fold increasing in GLUT1 mRNA at lactation (p < 0.05) and 2-fold at protein level for GLUT1 and GLUT8 (p < 0.05 and 0.01, respectively). The temporal expression pattern was shared with cytokeratin 18 and Ki67 (p < 0.01). Endogenous GLUT8 partially co-localized with 58 K protein and α-lactalbumin in mammary tissue and with Golgi membrane–associated protein 130 in isolated epithelial cells. The spatial-temporal synchrony between expression of GLUT8/GLUT1 and alveolar cell proliferation, and its localization in cis-Golgi associated to lactose synthase complex, suggest that both transporters are involved in glucose uptake into this organelle, supporting lactose synthesis.

中文翻译：

---

GLUT1和GLUT8支持鼠乳腺上皮细胞在高尔基体中的乳糖合成。

乳腺在怀孕和哺乳期间增加了能量需求，以支持上皮增殖和牛奶营养素的合成。乳糖是牛奶中的主要碳水化合物，是通过葡萄糖和UPD半乳糖中的乳糖合酶在乳腺上皮细胞的高尔基体中合成的。我们研究了乳腺中GLUT1和GLUT8表达的时间变化及其与BALB / c小鼠中乳糖合成和增殖的关系。使用六组：处女，在第2和17天怀孕，在第2和10天哺乳和在第2天断奶。通过qPCR，蛋白质印迹和免疫组织化学方法研究了GLUT1和GLUT8转运蛋白的时间表达及其在乳腺组织中与乳白蛋白，Ki67和细胞角蛋白18的关系，以及亚细胞定位。p  <0.05）和GLUT1和GLUT8蛋白水平的2倍（ 分别为p <0.05和0.01）。时间表达模式与细胞角蛋白18和Ki67共享（p  <0.01）。内源性GLUT8与58 K蛋白和α-乳白蛋白在乳腺组织中部分共定位，并与高尔基膜相关蛋白130在分离的上皮细胞中共定位。GLUT8 / GLUT1的表达与肺泡细胞增殖之间的时空同步，以及其在与乳糖合酶复合物相关的顺式高尔基体中的定位，表明这两种转运蛋白均参与了该细胞器中葡萄糖的吸收，从而支持了乳糖的合成。