Nuclear receptors – regulate key functions
Nuclear receptors regulate key functions in the body affecting many major diseases such as dyslipidemia, diabetes, obesity, inflammation and osteoporosis. Through receptors it is also possible to affect the growth of certain cancers. To date, 48 different nuclear receptors have been identified that are assumed to be of relevance for humans. Around 10 percent of today's medicines act through nuclear receptors.
Nuclear receptors are activated naturally by the hormonal system. Hormones are produced in one organ and transported by the blood stream to one or more target organs, where they exercise their effect. In the target organ, the hormone binds to a protein, called a receptor. There are receptors on the surface of the cell as well as inside the cell. It is the receptors inside the cell that are called nuclear receptors.
Nuclear receptors function as a switch for the transcription of genes in the specific cell at that very moment and therefore what proteins the cell contains. One specific hormone-nuclear receptor complex may have different effects in different tissues. The hormone cortisol, secreted by the adrenal glands and transported via the blood stream, can for example regulate the gene expression in inflamed tissue, so that anti-inflammatory proteins are stimulated and inflammation-inducing proteins are inhibited. In the liver, it can reduce blood sugar production by controlling the amount of proteins involved.
Some nuclear receptors are activated or inhibited by hormones, others by vitamins, fatty acids or bile acids. In some cases, the natural signaling molecule, known as the ligand, is unknown. The natural ligands fit into binding pockets at the nuclear receptors. By designing drugs that in a similar manner bind to the nuclear receptors, gene expression can be affected, which is useful in treating many diseases and medical conditions.
