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Fig. 2 | Journal of Animal Science and Biotechnology

Fig. 2

From: Recent progress of porcine milk components and mammary gland function

Fig. 2

Lactose synthesis pathway in porcine mammary gland. Note: Glucose is taken up by the porcine mammary gland through membrane glucose transporters (possibly GLUT1). In the cytoplasm, after glucose is converted into glucose-6-phosphate, it will be further converted into UDP-galactose by a series of enzymes: PGM, UGP2, GALT, and GALE. Subsequently, glucose and UDP-galactose in the cytoplasm is transported into the Golgi bodies by GLUT1 (possibly) and SLC35A2, respectively. Finally, glucose and UDP-galactose are synthesized into lactose by LALBA and B4GALT1 in the Golgi bodies. After the initation of lactation, mRNA of enzymes is increased 2-fold or more are shown in light purple; those increasing 1.5-to1.9-fold are colored light red, and those expression increase or decrease less than 1.5-fold are shown in light gray. Abbreviation: GLUT1, glucose transporter-1; PGM, phosphoglycerate mutase; UGP2: UDP-glucose pyrophosphorylase 2; GALT, galactose-1-phosphate uridyltransferase; GALE, e UDP-glucose 4-epimerase gene; LALBA, alpha-lactalbumin gene; β-1,4-galactosyltransferase

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