UVM Theses and Dissertations
Format:
Print
Author:
Bentley, Pamela A. P.
Dept./Program:
Animal Sciences
Degree:
MS
Abstract:
Glucose uptake in the bovine mammary gland is essential to the production of lactose and therefore plays a key role in milk synthesis. Facilitative glucose transporters (GLUTs) mediate glucose transport in the mammary gland. GLUT1 is the major facilitative glucose transporter expressed in bovine mammary gland and has been shown to localize to the basolateral membrane of mammary epithelial cells. GLUT1 is therefore thought to play an important role in glucose uptake during lactation. The objective of this study was to determine the transport kinetic properties of bovine GLUT1 using the Xenopus oocyte model. Bovine GLUT1 was expressed in Xenopus oocytes by microinjection of in vitro transcribed cRNA and was found to be localized to the plasma membrane, which resulted in increased glucose uptake.
This bGLUT1mediated glucose uptake was dramatically inhibited by cytochalasin B and phloretin. Kinetic analysis of bovine GLUT1 was conducted under zero-trans conditions using radio-labeled 2-deoxY-D-glucose and the principles of Michaelis-Menten kinetics. Bovine GLUT1 exhibited a Km of 7.69 ±1.7 mM for 2-deoxY-D-glucose. Transport by GLUT1 was inhibited by mannose and galactose, but not fructose. Our data provides insight into the role of bovine GLUT1 in supplying the mammary gland with glucose during milk synthesis.
This bGLUT1mediated glucose uptake was dramatically inhibited by cytochalasin B and phloretin. Kinetic analysis of bovine GLUT1 was conducted under zero-trans conditions using radio-labeled 2-deoxY-D-glucose and the principles of Michaelis-Menten kinetics. Bovine GLUT1 exhibited a Km of 7.69 ±1.7 mM for 2-deoxY-D-glucose. Transport by GLUT1 was inhibited by mannose and galactose, but not fructose. Our data provides insight into the role of bovine GLUT1 in supplying the mammary gland with glucose during milk synthesis.