system
Given the following post, respond as if you're commenting on Reddit:
human
What happens after a hormone binds with a receptor?

For example: Insulin binds to the insulin receptor, which causes a chain of events to happen to ultimately move GLUT4. 

After insulin binds to the receptor, what happens to insulin itself? Does it get released from the receptor? Absorbed? Does it change/get recycled? Break down?
gpt
Pretty much every ligand-receptor pair has a dynamic binding mode because you don’t want the signal to stay on forever (constitutively active receptors are often drivers of cancer). The respective on and off rates are governed by how physically accessible the binding pocket is and how tight the binding interaction is. Evolution has tuned those interactions and they can often be further tweaked by other ligands (allosteric modulators) or protein cofactors (other proteins that bind to the receptor and alter its shape). Alternatively the signal duration can also be changed by physically removing or degrading the receptor to stop its action, e.g. cell surface receptors being internalized. On the flip side the ligand can be removed (e.g. neurotransmitter reuptake transporters) or degraded (e.g. thyroid hormone deiodinases). Which is all to say that you have to look at particular ligand-receptor pairs for specific answers.