What is cytosolic cyclic AMP

Healthy Person P takes a new drug that is a member of a drug family that results in  constant levels of cytosolic cyclic AMP (cAMP) in one and only one cell type in the body.   A single dose of each member of the new drug family works within one hour and lasts for  one week.  Which of the following is true for P one day after taking a specific member of  the new drug family?

  A.  Consider the situation that P takes Drug A that produces constant very low levels of cytosolic cAMP in the epithelial cells of the medullary collecting duct of the kidney.  One day after taking Drug A, the water permeability of the luminal membranes of these cells in P will be higher than pre-drug levels.

  B.  Consider the situation that P takes Drug B that produces constant very low levels of cytosolic cAMP in the SA node cells of the heart.  One day after taking Drug B, P's heart rate will be higher than pre-drug levels.

  C.  Consider the situation that P takes Drug C that produces constant very high levels of cytosolic cAMP in the cells of the liver.  Ignore any effects due to insulin binding to insulin receptors in the liver.  One day after taking Drug C, the amount of glycogen in P's liver cells will be higher than pre-drug levels.