The hormones that are soluble in lipids are known as lipid-soluble hormones. Steroid hormones such as testosterone and estrogen are examples of lipid-soluble hormones. These hormones easily diffuse through the plasma membrane as the membrane is made of a phospholipid bilayer. Once the hormone enters the cytoplasm, it either binds to the receptors present in the cytoplasm or the nucleoplasm.
The binding of hormone with its receptor leads to the formation of a hormone-receptor complex that alters the activity of the cell. This complex affects the transcription of genes and either upregulates (increases) or downregulates (decreases) the production of specific proteins. The mRNA (messenger ribonucleic acid) initiated by the hormone leaves the nucleus and directs the formation of a new protein. These new proteins are used by the cell, thereby altering its activity. The hormone-stimulated changes in the cell take a measurable amount of time- more time than is needed to simply alter the function of a protein already in the cell.
The biological control for the lipid-soluble hormone lies inside the nucleus.
The receptor for lipid-soluble hormones lies in the cytoplasm or nucleoplasm of the cell.