Intracellular receptor

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Intracellular receptors are globular protein receptors located inside the cell rather than on its cell membrane. The word intracellular means "within or inside a cell." Molecules that cross a cell membrane to bind with a receptor are generally nonpolar and may be relatively small. These molecules are also known as ligands. Hormones that use intracellular receptors include thyroid, aldosterone, and steroid hormones.^[1]

Examples are the class of nuclear receptors located in the cell nucleus and cytoplasm and the IP₃ receptor located on the endoplasmic reticulum. The ligands that bind to them are usually intracellular second messengers like inositol trisphosphate (IP₃) and extracellular lipophilic hormones like steroid hormones. Some intracrine peptide hormones also have intracellular receptors.