Fig. 3

Effect of glucose on expression of genes involved in lactose synthesis. a Quantitative real-time PCR analysis of the mRNAs encoding glucose and UDP-galactose transporters, including glucose transporter 1 (GLUT1), glucose transporter 4 (GLUT4), glucose transporter 8 (GLUT8), glucose transporter 12 (GLUT12), solute carrier family 35 member A2 (SLC35A2), and solute carrier family 35 member B1 (SLC35B1). b Quantitative real-time PCR analysis of the mRNAs encoding key enzymes and regulators in the lactose synthesis pathway, including hexokinase-2 (HK2), α-lactalbumin (α-LA), β-1,4-galactosyltransferase 1 (β4GalT-I), and protein kinase B alpha (AKT1). For a and b, total RNA was isolated from dairy cow mammary epithelial cells treated with or without 12 mM glucose for 24 h. The mRNA levels were measured by qPCR and normalized to β-ACTIN mRNA. c, d Western blot analysis (c) and quantification (d) of proteins involved in lactose synthesis. e, f Western blot analysis (e) and quantification (f) of AKT1 and pAKT1. For c and e, protein lysates from dairy cow mammary epithelial cells treated with or without 12 mM glucose for 24 h were collected for western blot analysis. Data are shown as the mean ± SEM from 3 independent replicates. *P < 0.05; **P < 0.01; NS, no statistical significance