D-glucose uptake in human liver cell cultures

Area of Science:

• Cellular Biology
• Metabolic Biochemistry

Background:

• D-glucose uptake is crucial for liver function and energy metabolism.
• Understanding glucose transport mechanisms is key to metabolic disease research.

Purpose of the Study:

• To elucidate the kinetic parameters of D-glucose transport in human liver cell cultures.
• To identify distinct D-glucose transport systems and their characteristics.
• To investigate the effect of cytochalasin B and hereditary fructose intolerance on glucose uptake.

Main Methods:

• Kinetic analysis of D-glucose uptake across a wide concentration range (0.005–30 mmol/l).
• Employing cytochalasin B to assess inhibition of specific glucose transport sites.
• Comparing D-glucose uptake in cell lines from hereditary fructose intolerance patients versus control lines.

Main Results:

• Evidence for two distinct D-glucose transport systems: high-affinity (Km ≈ 0.65 mmol/l, Vmax ≈ 12.5 nmol/mg/min) and low-affinity (Km ≈ 6.9 mmol/l, Vmax ≈ 80 nmol/mg/min).
• Cytochalasin B selectively inhibited the high-affinity D-glucose transport system at 2.1 x 10(-7) mol/l.
• Significantly elevated D-glucose uptake observed in cell lines from hereditary fructose intolerance patients compared to controls.

Conclusions:

• Human liver cells possess at least two kinetically distinct D-glucose transport systems.
• The high-affinity system is sensitive to cytochalasin B.
• Altered D-glucose uptake kinetics are associated with hereditary fructose intolerance, suggesting a role in the disease pathophysiology.