Intracellular Receptors

The receptors present within the cells, typically in the cytoplasm or nucleus, are proteins referred to as intracellular receptors. 

The ligands of intracellular receptors are often small, hydrophobic (hating) molecules because they must cross the plasma membrane to reach their receptors. For instance, intracellular membranes serve as the main receptors for hydrophobic steroid hormones, including the sex hormones estradiol (an estrogen) and testosterone.

When a hormone enters a cell and attaches to its receptor, the receptor is altered, allowing the complex of the receptor and hormone to enter the nucleus and control gene activity. Regions of the receptor that are capable of attaching to particular DNA sequences are made visible by hormone binding. These sequences are located near to specific genes in the cell’s DNA, and when the receptor binds there, it changes the transcription rate of those genes.

In biochemistry and pharmacology, receptors are protein-based chemical structures that receive and transmit signals that can be integrated into biological systems. A ligand is an ion or molecule that binds to a central metal atom to form a coordination complex in coordination chemistry. Bonding with metals typically entails the formal donation of one or more of the ligand’s electron pairs, often via Lewis Bases Although there are many kinds of receptors, they can be categorized into two groups: 

• Cell surface receptors, which are found in the plasma membrane, and 
• Intracellular receptors are found inside the cell.