Gluco- and mineralocorticoid receptors
GCs bind to intracellular receptors, as they can diffuse through the plasma membrane, as seen in figure 2. GC and MC receptors(GR and MR) can form homodimers and heterodimers or remain as monomers, allowing them to pass on various kinds of signals. Monomers can interact with transcription factors and repress stress responses such as peptide synthesis (such as CRH and vasopressin), blocking stress responses going on. This is not always the case though, as GR dimers can cause increases in CRH in extrahypothalamic areas. Cortocosteroid receptor function interacts with neurotransmitter and neuropeptide function and stress responsiveness is memorized and maintained in the case of something similar happening in the future(de Kloet et al, 2005).
GCs can induce gene expression changes; MR or GR activation leads to altered expression of 70 to 100 genes. Half of these genes were upregulated, and gene responsivity to receptor type differed.
Many of these genes influence receptors and ion pumps, as seen in figure 2. GCs (steroids) bind to MRs or GRs and consequently bind to the GRE and RE genes. GRE and RE activation leads to various other protein activation. GCs can also function as neurosteroid, which can directly interact with and influence GABA receptors (De Kloet et al, 2005).
Effects of GCs on the periphery
To begin with, GCs are released into the periphery of the body. They facilitate responses to stressors by changing the metabolism of lipids and energy production and dampen acute stress and immune/inflammatory responses so they do not overshoot (de Kloet et al, 2005). Though the first wave of acute stress activates the immune system (Sapolsky et al, 2000), GCs inhibit synthesis of cytokines a...
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