Each cell has specific phenomenon of interacting with other cells and there are specific proteins present through which interaction takes place. Such class of proteins is called as receptors. All the organisms have specific code of genes which regulate the functioning of receptors. Several molecules, such as hormones, neurotransmitters, cytokines and steroids, are present which help in the activation of these receptors.
There are different types of groups based on their behavior towards water molecules. They are divided into two categories namely, hydrophilic and hydrophobic. Hydrophobic groups are water hating and hydrophilic group are water loving.
Cell membrane is made up of two components, broadly classified as proteins and phospholipids. The lipid present in the outer membrane is phosphatidylcholine and the inner membrane consists of phosphatidylethalomine and some other phospholipids. These phospholipids are hydrophobic in nature due to the presence of bulky molecular weight and carbon atoms.
Adrenaline and steroids, such as estron, show different behaviors towards the protein interaction. As steroids are hydrophobic in nature similar to the cell membrane, they can cross the cell membrane easily. On the other hand, adrenaline, which is a hydrophilic hormone, cannot cross the cell membrane due to the difference in its nature from the cell membrane.