Question

Some scientists believe that fructose is particularly bad for human health because it promote fat synthesis, contributing to development of type II diabetes and fatty liver disease. You are a scientist working for a lab attempting to develop a drug to help with such diseases called fructono. The idea is that fructono could be added to the diet to reduce fructose absorption; even though fructono would be absorbed, it would not be metabolized, and would be excreted by the kidney. The hypothesis is that fructono binds to the fructose transporter, competitively displacing fructose. This cannot be easily studied in humans, so you are investigating this hypothesis with a mouse small intestine, which is known to transport fructose using a transporter that is quite similar in amino acid sequence and structure to the human protein. For your research, you set up a perfused intestine prep. You cut out about 1 cm of small intestine, and put it in a dish containing saline. You insert a tube into the intestinal section, and use a pump to push any fluid you want through the lumen of the intestine. You have radio-labeled fructono, so you can measure its appearance in the saline outside the intestine. How can you measure the rate of transport of fructono? 1 pt Describe experiments that would test whether the absorption of fructono is protein-mediated vs. passive (just leaking through cracks, or diffusing through membranes). What results will you get if the transport is protein-mediated vs. passive? 2 pts. Describe experiments that would test whether the absorption of fructono is active, and the predicted results if transport is active or not. 2 pts. Describe experiments that will test whether the active transport of fructono requires luminal Na+, and the predicted result if transport is Na+-dependent or not. 1 pt. Describe experiments that will test whether fructono can reduce the transport of fructose in a dose-dependent manner. 2 pts What side-effects might fructono have? 2 pts

Answer 1