Plasma membranes AS biology question

This is just based on AS biol. knowledge...
The hormone glucagon is a protein. It targets liver cells but does not affect any other cells in the body. Explain why.

Help pleaseee?!? Thanks!:)

Glucagon acts via a hormone receptor in the cell membrane (which acts through G-proteins). The glucagon receptor is mainly present in liver cells. As it is also found in kidneys and to lesser amounts in other tissues it would not affect only liver cells. But it would only affect cells which have the receptor.

Liver cells have the glucagon receptor on the cell membrane - other cells do not.