Question

1. The investigators considered the possibility that lactate did not have its own transporter, but instead used the general anionic transporter in liver cells. In order to test this hypothesis, they measured the up 2 4 take of 0.4 mM [ C] lactate in the presence of 10 mM Na SO and found that lactate transport 14 was 2 4 inhibited 11% in the presence of the Na SO . (The sulfate ion is transported by the general anionic transporter.) Do these results indicate that lactate utilizes the general anionic transporter? Explain

2. Consider the structure of lactate–do you think that lactate would easily pass through the plasma membrane by simple diffusion? Explain why or why not.

3. Transport of lactate from the blood to the liver is part of the Cori cycle. Draw a diagram of the Cori cycle. Under what physiological conditions would you expect the Cori cycle to be active?

Answer 1