Steroid corticoid receptor

When only limited amounts of cells are available (e.g., of human leukocytes for estimation of corticoid receptors or of human skin fibroblasts for estimation of androgen receptors) an estimation of receptors in separated cell fractions might not be feasible. Total numbers of binding sites per cell may be obtainend if different concentrations of suitable highly specific ligands are used and incubation conditions of intact cells are carefully calibrated. In addition a good separation between medium with free steroid or steroids loosely adsorbed to the cell surface and steroid bound to the receptor inside the cell is essential. 

Adrenal cortical hormones are controlled by the hypothalamus, which secretes corticotropin-releasing hormone (CRH) in response to stress situations. CRH, then, causes the anterior pituitary gland to release corticotropin into the circulation. Adrenal cortical surface receptors are then stimulated by corticotropin to produce and release the corticoid steroids. 

Following the penetration of the cell membrane, corticoids bind with specific cytoplasmic receptors. These receptors have been demonstrated in all target tissues including the skin [4, 17]. After modification, the steroid-receptor complex enters the nucleus, where it interacts with DNA to alter the production of mRNA induced locally by RNA polymerase. This mRNA moves into the cytoplasm, where it attaches to ribosomes and acts as a template for protein synthesis. 

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