The receptors for catecholamine and polypeptide hormones are found?

The cell membrane

Catecholamine hormones, such as epinephrine and norepinephrine, and polypeptide hormones, such as insulin and glucagon, exert their effects by binding to receptors located on the cell membrane. These receptors are specialised proteins that recognise and bind to specific hormones, initiating a cascade of intracellular events that ultimately lead to a cellular response.