Question

Some of Hirschhorn et al.’s results from administering solutions with varying concentration of glucose are shown in Figure 5.

Figure 5. Effect of increasing concentrations of glucose in perfusion solutions on net stool output rate. Figure developed from data in Hirschhorn et al., 1968.

Part H - Effect of added glucose on stool output in cholera

Which statement best explains the effect of increasing glucose concentration in the perfusion solution on net stool output rate?

Glucose had no effect because electrolytes administered through the tube always decreased the net stool output rate, regardless of the glucose levels.

Absorbing a greater quantity of glucose increased fluid absorption and thereby decreased the net stool output rate.

More glucose in the perfusion solution meant that there was less water in the solution to make stool with.

Stool production was decreasing over time as the patients recovered from cholera, and adding glucose did not change the rate of this decrease.

Why didn’t net stool output rate decrease significantly with fructose?

Fructose absorption does not bring as much water because fructose has a smaller molecular weight than glucose and galactose.

Fructose can’t be absorbed without glucose in the intestine.

Fructose absorption doesn’t require sodium transport and results in a lower solute transport and lower water absorption.

GLUT transporters only transport hexose sugars, and fructose has a 5-carbon ring, not a 6-carbon ring.

GLUT transporters only transport sugars that start with G.

Answer 1

Effect of increasing glucose concentration in the perfusion solution on net stool output rate as Stool production was decreasing over time as the patients recovered from cholera, and adding glucose did not change the rate of this decrease.

Net stool output rate decrease significantly with fructose due to Fructose absorption does not bring as much water because fructose has a smaller molecular weight than glucose and galactose.Since intestinal sodium absorption was so enhanced by an actively transported sugar, fructose and galactose perfusion fluids were prepared, and it was found that fructose was less well absorbed than glucose or galactose: in general, the results with these sugars were consistent with the sodium-dependent active transport of galactose and the passive transport of fructose, unrelated to sodium transport.