L4 - adrenal cortex, glucocorticoids Flashcards
what are adrenal cortx hormones
corticosteroids, androgens
what are adrenal cortx hormones
corticosteroids, androgens
types of corticosteroids
glucocorticoids, mineralcorticiouds
what are adrenal cortex hormones dervived from
cholostral, synthesised from acetyl CoA or taken from circulation
what enzymes used to synthesise corticosteroids
P450 cytochrome enzymes
three zona of adrenak cortex
glomerulusa, fasciculata and reticularis
- each zona produce diff hormones
what bond is important in the cholestral structure and why
C20-22, cos this bond will be metabolised into other metabolites and hormones
how to start any adrenal steriodogenesis from cholestral
cholestral taken up by mitochondria through StaR step
where is Star located in the mitochondria
its membrane
what happens to cholestral once it is in matrix
becomes pregnenolone
struture of star protein
has cholestral transfer protein
what molecules promotes and suppress star protein ( regulation of star )
ACTH, LH for promotion
Alcohol for supression
what enzymes catalsyses the conversion from cholestral to pregn
P450scc
reactions involving P450scc
scc in the name means side cleavge
- first - 2 hydrolxylase reactions
- second - cleavage of the bond
what does P450scc need for function
electrons from a donor molecule
what are the two proteins that work with P450scc in a complex
adrenodoxin reductase and adrenodoxin
what molecule induces the gene expression in this P450scc complex
ACTH
how many C in glucocorticoids (glucort)
21
eg of glucort
cortisol and corticosterone (inactive form of cortisol)
cortisol function
hormone for stress
how is cortisol transported in the blood and why
cortisol is lilophilic so its hard for it to travel in blood effeciently
- 90% bound to plasma protein like transcortin and albumin
pathway of producing cortisol and what axis is this
hypoth release releasing factor (CRH)> anteroir pituitary release ACTH> adrenal coretx > cortisol made
- HPA axis
how to generate ACTH
cleaved from prohormone of POMC
mechanism of action of glucort
as glucort receptors
actions of glucort , -metabolism using carbohydrates
- glucose level increases through gluneogenesis
- stops glucose entry in tissues
actions of glucort , metabolsim of proteins
in muslces, protein broken down so muslce wastage
action of glucorts in liver
increases AA uptake for protein synthesis and gluconeogenesis
action of glucort, metabolsim of fat
FA mobilised for gluneogensis in adipose tissues
-redistribution of fat around face, abdominal area
action of glucort in electro lyte balance
when there is large amount of glucort- there are mineralcort activity
action of glucort in bones
decreases absorption of calcium and increaces excretion
action of glucort in cns
mood
cognition
action of glucort in IS
decreases levels of lymphocytes (weak IS) and increases neutrophils, RBC and platelets
therapeutic action of glucort
reduces inflamm bu reducing leukocyte action
- reduced allergies by decreasing histamine synthesis
what happens if there’s excess glucort
leads to cushings syndrome
- makes a tumour in pituitary
- adernal adenoma
- ACTH prodcuted too much since it doesn’t respond to neg feedback
treatment for cushings syndrome
surgery, radiotherapy, drugs (11 hydroxylase inhibitor - doesn’t make cortisol)
primary and secondary disorder associated with decreased adrenal function
primary - autoimmune like addisons disease
-seco-pituitary disease so decreases ACTH
symptoms of addisions disease
fatigue, weight loss, ion imbalance
treatment in addison disease
cortisol replacement therapy