HORMONS & NT Receptors

A hormone receptor is a receptor molecule that binds to a specific hormone. Hormone receptors are a wide family of proteins. There are two main classes of hormone receptors. Receptors for peptide hormones tend to be cell surface receptors (trans membrane receptors). An example of this is Growth Hormone. The Receptors for steroid hormones are usually found within the cytoplasm and are referred to as intracellular or nuclear receptors, such as estradiol.

A neurotransmitter receptor is a membrane receptor protein. There are two major types of neurotransmitter receptors :  ionotropic and metabotropic. Ionotropic means that ions can pass through the receptor, whereas metabotropic means that a second messenger inside the cell relays the message. Metabotropic receptors are in fact G protein-coupled receptors. Ionotropic receptors are also called Ligand-gated ion channels and they can be excited by neurotransmitters (ligands) like glutamate and aspartate.