Corticoid hormones Receptors

An example of the importance of enzymatic modification of hormones for the tissue specificity of hormone action is the effect of the mineral corticoid aldosterone in the presence of a large excess of the glucocorticoid cortisol. Aldosterone regulates the Na -export and K -retention in the kidney by binding on the aldosterone receptor. 

Aldosterone, which is classified as a mineralo-corticoid, is produced under the control of the renin-angiotensin hormone system (Box 22-D), which is stimulated when sodium ion receptors in the kidneys... 

PURPOSE AND RATIONALE For all new compounds which have some structural similarity or relation to the corticoid scaffold. There are now many such test systems which measure the initial membrane binding to the ACTH receptor, and to define the initial steps of hormone-related activation. However the binding affinity does not necessarily imply biological activation e.g. of adrenal cortical cells. Therefore, such tests always need to be followed up by a in-vitro testing on adrenal glands or dispersed adrenal cells. 

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. 

The promotion of mammary development, lactation, and galactopoiesis requires growth hormone, ovarian estrogen (duct formation), ovarian progesterone (lobule-alveolar development), and adrenal corticoids, as well as prolactin and oxytocin. The secretion of prolactin is modified by snbstances that stimulate or block dopamine-receptor sites. Agents such as neuroleptics (chlorpromazine) may cause lactation in a nonpregnant woman. On the other hand,... 

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