03.02.1.2 Intracellular Receptors

An example of an intracellular receptor is the receptors for the glucocorticoids, which are the steroids produced by the adrenal cortex. The physiological glucocorticoids, such as hydrocortisone (H) diffuse into cells. The cells that are regulated by glucocorticoids have intracellular receptors (R) for glucocorticoids. Stimulation of intracellular receptors leads to transcription of target genes (Tr), which modulate the proteins made be the cell (Figure 3.17).

Figure 3.17 Intracellular receptors (Copyright QUT, Sheila Doggrell)

The physiological action of the glucocorticoids that pharmacologists are particular interested in is their anti-inflammatory actions. These are not very pronounced with the physiological glucocorticoids, but changes to the glucocorticoid structure have produced more potent anti-inflammatory agents. Beclomethasone is a potent synthetic glucocorticoid that mimics the effects of hydrocortisone. Beclomethasone is used as an anti-inflammatory agent in the treatment of asthma, where it is used to decrease the inflammation and reduce the likelihood of having an asthma attack.