# biology a level question help

Hi, could someone please explain why the mass of the gut content increases at high concentrations of Tenapanor. (sorry bit of a wordy question) :

Scientists investigated the use of a drug called Tenapanor to reduce salt absorption in the gut. Tenapanor inhibits the carrier protein, NHE3. The scientists fed a diet containing a high concentration of salt to two groups of rats, A and B.
The rats in Group A were not given Tenapanor (0 mg kg−1).
The rats in Group B were given 3 mg kg−1 Tenapanor.

One hour after treatment, the scientists removed the gut contents of the rats and immediately weighed them. Their results are shown in the table.

A (conc of Tenapanor) - 0
A( mean mass of content of gut) - 2g
B (conc of Tenapanor) - 3
B (mean mas of content of gut) - 4.1g

The scientists carried out a statistical test to see whether the difference in the means was significant. They calculated a P value of less than 0.05. They concluded that Tenapanor did reduce salt absorption in the gut. Use all the information provided and your knowledge of water potential to explain how they reached this conclusion.
In group A, the cells of the gut absorb a lot of the salt the rats have consumed, decreasing the water potential in these cells, causing water (from blood/tissue fluid?) to flow into the cells by osmosis.

In group B, because the carrier proteins are inhibited by the tenapanor, the cells of the gut take up less salt, so they have a higher water potential, so less water moves into the cells by osmosis than in group A.

This conclusion is supported by their p-value: because it is less than 0.05, there is a less than 5% chance it happened randomly/by chance.

hope this helps (:
Original post by 0gg
In group A, the cells of the gut absorb a lot of the salt the rats have consumed, decreasing the water potential in these cells, causing water (from blood/tissue fluid?) to flow into the cells by osmosis.
In group B, because the carrier proteins are inhibited by the tenapanor, the cells of the gut take up less salt, so they have a higher water potential, so less water moves into the cells by osmosis than in group A.
This conclusion is supported by their p-value: because it is less than 0.05, there is a less than 5% chance it happened randomly/by chance.
hope this helps (:

That helps, thank you 😀
Original post by 0gg
In group A, the cells of the gut absorb a lot of the salt the rats have consumed, decreasing the water potential in these cells, causing water (from blood/tissue fluid?) to flow into the cells by osmosis.
In group B, because the carrier proteins are inhibited by the tenapanor, the cells of the gut take up less salt, so they have a higher water potential, so less water moves into the cells by osmosis than in group A.
This conclusion is supported by their p-value: because it is less than 0.05, there is a less than 5% chance it happened randomly/by chance.
hope this helps (:

Surely that would make the drug a bad thing then as its causing water to leave your cells
Original post by Fesdces
Surely that would make the drug a bad thing then as its causing water to leave your cells

According to Wikipedia, tenapanor is used to treat constipation caused by IBS.