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hormones of the Hypothalamic-Adenohypophyseal-Adrenocortical Axis
CRH (corticotropin releasing hormone), ACTH (adrenocorticotropic hormone), steroid hormones (corticosteroids)
CRH secretion is stimulated by this
stressful physical, chemical, and emotional stimuli such as trauma, exercise, hemorrhage, pain, hypoglycemia, LPS, overcrowding, extreme temps.
this causes too much production of ACTH
destruction of adrenal cortex (less cortisol to perform negative feedback inhibition)
ACTH promotes the uptake of this substance in all three zonae of the adrenal cortex so they can enzymatically convert it into aldosterone, cortisol, and estradiol
ACTH promotes mitosis/growth, overall health and integrity, but does not directly stimulate the pathway to make this
these substances do not influence the production of CRH or ACTH, only cortisol does
aldosterone & estradiol
in Cushing's, the adenohyphysis is not listening to cortisol negative inhibition feedback, so it keeps making this
in Cushing's, overproduction of ACTH causes this to happen
adrenal cortex overproduces cortisol which exerts excessive negative feedback inhibition on the hypothalamus to reduce production of CRH
in Cushing's, even though the hypothalamus's production of CRH is inhibited, ACTH is still being made because of this
only a small amount of CRH is needed to stimulate the adenohypophysis to make ACTH
ACTH causes increased glucose entry, glycogenolysis, and glycolysis at these zonae
fasciculata and reticularis
ACTH turns on enzymes but needs these 2nd messengers because it's stuck at the membrane
cAMP and PKA
ACTH is not actually needed at this zona because increased K+ and angiotensin II stimulate its pathway
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