Question

a hormone may be
multiple choice
inactivated by its target cell.
activated by its target cell.
inactivated by nontarget cells.
excreted before it has a chance to act on a target cell.
all of the choices could be correct.

Explanation:

• Hormones can be inactivated by their target cells after exerting their effects. For example, some hormones bind to receptors on target cells, and after the signaling process, they are metabolized or inactivated within the target cell.
• Hormones can also be activated by their target cells. Some hormones are released in an inactive form (pro - hormones), and the target cells have enzymes that convert them into the active form.
• Non - target cells can inactivate hormones. Since hormones circulate in the bloodstream, non - target cells may have enzymes that can break down or inactivate the hormones.
• Hormones can be excreted before reaching their target cells. For instance, if the hormone is filtered out by the kidneys (in the case of peptide hormones) or metabolized in the liver and then excreted before it can bind to its specific target cell receptors.

Answer:

All of the choices could be correct.