When adenylate cyclase is activated by a hormone, the concentration of cyclic AMP increases in the cell even though the hormone does not enter the cell. This is an example of the __________________ mechanism of hormone action.
A) altering membrane transport
B) altering activity of DNA
C) second messenger
D) all of above

Question

Quizplus · Accepted Answer

Activation of adenylate cyclase by a hormone leads to the production of second messengers such as cyclic AMP, which amplify and propagate the signal within the cell. This is a common mechanism of hormone action for many hormones, including epinephrine, glucagon, and vasopressin. Altering membrane transport and altering activity of DNA are also mechanisms of hormone action, but they do not account for the increase in cyclic AMP concentration in the cell. Therefore, the correct answer is C.

When Adenylate Cyclase Is Activated by a Hormone, the Concentration