Hormonal Mechanism Type 1
The endocrine system release hormones that trigger the actions in a target cell. Target cell membrane receptor will bind only to one type of hormone. Hormones (messengers) act with enzymes (catalyst) to invoke changes within the target cells. Hormonal action can be gained by knowing the type of receptor it uses. The receptors can be categorized into two types based on the location on the cell:
- Cell surface receptors
- Hormones: Peptide hormones, proteins, catecholamines and eicosanoids
- The Principle Mechanism of Action is the generation of second messengers which reacts the activity of other molecules within the cell
- Intracellular receptors
- Hormone: Steroids and thyroid hormones
- The Principle Mechanism of Action is alter the activity of responsive genes in the hormones
Cell Surface Receptors or Hormonal Mechanism of Action Type 1
In type 1 hormonal mechanism, only the receptor found on the surface of the cell will come in contact with the specific hormone. This receptor when in combination with the hormone will initiate biochemical processes such as muscle contraction and relaxation, digestion, etc.
Peptide hormones, proteins, catecholamines and eicosanoids find their receptor on the plasma membrane of the target cells. The binding of hormone to the receptor will initiates a series of events that will leads to production of second messengers within the cell. Second messengers then will trigger a series of molecular interactions that will alter the physiologic state of the cell.
Each of the hormones has unique structure that will bind to the receptor protein that are embedded in the cytoplasmic membrane on the target cell. Near the receptor protein is adenylate cyclase which is in inactive form before the hormone will arrive at the target cell and will bind to its receptor.
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References: Clinical Chemistry by Bishop