Biochem 3: Adrenals Flashcards
cholesterol derivative hormones are what type of hormones
steroid hormones
in which part of the adrenals are steroid hormones made
the cortex
Which hormones are created where in the adrenal cortex?
Zona glomerulosa: mineralocorticoids (aldosterone)
Zona fasciculata: glucocorticoids (cortisol)
Zona reticularis: androgens (DHEA
What type of hormones are located in the medulla, name the 3 hormones too?
catecholamines from tyrosine
NE, Epi, Dopamine
Explain how ACTH is important in synthesis of adrenal cortex hormones
Starts the cascade effect of hormone production when ACTH (released from AP) acts on the Gs (cAMP) receptor
What is the cascade effect in synthesis of adrenal cortex hormones
ACTH bind to Gs receptor –> activate PKA –>activate lipase.
Lipase then cleaves cholesterol esters to free cholesterol.
Free cholesterol is converted to the different hormones via mitochondrial reactions
what are steroid carrying proteins
proteins that are important in transporting steroid hormones to distant sites
why are steroid carrying proteins so important
steroid hormones are hydrophobic and so they must be attached to a protein
GIve an example of steroid carrying proteins
Cortisol binding protein/globulin
it carries:
1.cortisol
2. aldosterone
CBP is produced in the adrenals TRUE or FALSE
FALSE; they are produced in the liver
whats the point of cortisol-cortisone shunt
to prevent cortisol from binding to mineralocorticoid receptor (MR)
the concentration of cortisol is 1000x greater than aldosterone, which allows it to easily bind with MR causing AME
What happens when cortisol binds with MR
Apparent mineralocorticoid excess (AME)
- Conn Syndrome like effect – hyper-aldosteronism
- cortisol can activate MR so with a 1000x concentration of cortisol, its going to active it
what 2 hormones can bind to MR
cortisol and aldosterone
So how does the shunt prevent cortisol from binding with MR
converts cortisol into cortisone
cortisone can’t bind with MR receptor.
what 2 enzymes are involved in activating and inactivating cortisol
11B-HSD2 - inactivator of cortisol in the KIDNEY (cortisol–> cortisone)
11B-HSD1 - activator of cortisol in the LIVER (cortisone–>cortisol)
what is so special about the skin
has 11B-HSD1; allows cortisone cream to convert to cortisol (active form)
Thats why topical is effective
What is interesting about licorice
contains glycyrrhizic acid which INHIBITS 11B-HSD2.
this allows cortisol access to MR which leads to HTN and hypokalemia
What is the role of CYP450 in steroid hormones
convert free cholesterol to metabolite pregnenolone