A hormone receptor is a receptor protein on the surface of a cell or in its interior that binds to a specific hormone

Hormone

A hormone is a chemical released by a cell or a gland in one part of the body that sends out messages that affect cells in other parts of the organism. Only a small amount of hormone is required to alter cell metabolism. In essence, it is a chemical messenger that transports a signal from one...

. The hormone causes many changes to take place in the cell.

Binding of hormones to hormone receptors often trigger the start of a biophysical signal that can lead to further signal transduction pathways, or trigger the activation or inhibition of genes.

Types of Hormone Receptors

• Peptide hormone
  Peptide hormone
  Peptide hormones are a class of peptides that are secreted into the blood stream and have endocrine functions in living animals.Like other proteins, peptide hormones are synthesized in cells from amino acids according to an mRNA template, which is itself synthesized from a DNA template inside the...
  
   receptors are often transmembrane protein
  Transmembrane protein
  A transmembrane protein is a protein that goes from one side of a membrane through to the other side of the membrane. Many TPs function as gateways or "loading docks" to deny or permit the transport of specific substances across the biological membrane, to get into the cell, or out of the cell as...
  
  s. They are also called G-protein-coupled receptors, sensory receptor
  Sensory receptor
  In a sensory system, a sensory receptor is a sensory nerve ending that responds to a stimulus in the internal or external environment of an organism...
  
  s or ionotropic receptors. These receptors generally function via intracellular second messengers, including cyclic AMP (cAMP), inositol 1,4,5-trisphosphate (IP3
  Inositol triphosphate
  Inositol trisphosphate or inositol 1,4,5-trisphosphate , together with diacylglycerol , is a secondary messenger molecule used in signal transduction and lipid signaling in biological cells. While DAG stays inside the membrane, IP3 is soluble and diffuses through the cell...
  
  ) and the calcium
  Calcium signaling
  Calcium is a common signaling mechanism, as once it enters the cytoplasm it exerts allosteric regulatory effects on many enzymes and proteins...
  
   (Ca²⁺)-calmodulin
  Calmodulin
  Calmodulin is a calcium-binding protein expressed in all eukaryotic cells...
  
   system.

• Steroid hormone receptor
  Steroid hormone receptor
  Steroid hormone receptors are found on the plasma membrane, in the cytosol and also in the nucleus of target cells. They are generally intracellular receptors and initiate signal transduction for steroid hormones which lead to changes in gene expression over a time period of hours to days...
  
  s and related receptors are generally soluble proteins that function through gene activation. Their response elements are DNA sequences (promoters) that are bound by the complex of the steroid bound to its receptor. The receptors themselves are zinc-finger proteins. These receptors include those for glucocorticoids
  Glucocorticoid
  Glucocorticoids are a class of steroid hormones that bind to the glucocorticoid receptor , which is present in almost every vertebrate animal cell...
  
  , estrogen
  Estrogen
  Estrogens , oestrogens , or œstrogens, are a group of compounds named for their importance in the estrous cycle of humans and other animals. They are the primary female sex hormones. Natural estrogens are steroid hormones, while some synthetic ones are non-steroidal...
  
  s, androgen
  Androgen
  Androgen, also called androgenic hormone or testoid, is the generic term for any natural or synthetic compound, usually a steroid hormone, that stimulates or controls the development and maintenance of male characteristics in vertebrates by binding to androgen receptors...
  
  s, thyroid hormone
  Thyroid hormone
  The thyroid hormones, thyroxine and triiodothyronine , are tyrosine-based hormones produced by the thyroid gland primarily responsible for regulation of metabolism. An important component in the synthesis of thyroid hormones is iodine. The major form of thyroid hormone in the blood is thyroxine ,...
  
   (T3), calcitriol
  Calcitriol
  Calcitriol , also called 1,25-dihydroxycholecalciferol or 1,25-dihydroxyvitamin D3, is the hormonally active form of vitamin D with three hydroxyl groups...
  
   (the active form of vitamin D
  Vitamin D
  Vitamin D is a group of fat-soluble secosteroids. In humans, vitamin D is unique both because it functions as a prohormone and because the body can synthesize it when sun exposure is adequate ....
  
  ), and the retinoid
  Retinoid
  The retinoids are a class of chemical compounds that are related chemically to vitamin A. Retinoids are used in medicine, primarily due to the way they regulate epithelial cell growth....
  
  s (vitamin A
  Vitamin A
  Vitamin A is a vitamin that is needed by the retina of the eye in the form of a specific metabolite, the light-absorbing molecule retinal, that is necessary for both low-light and color vision...
  
  ).