Intracellular Receptors

Some messengers, such as thyroid hormone and steroid hormones, do not bind to membrane receptors but move directly across the lipid layer of the cell membrane and are carried to the cell nucleus, where they influence DNA activity. Many of these hormones bind to a cytoplasmic receptor, and together they are carried to the nucleus. In the nucleus, the receptor-hormone complex binds to DNA, thereby increasing transcription of messenger RNA (mRNA). The mRNAs are translated in the ribosomes, with the production of increased amounts of proteins that alter cell function.