what are GCs?
Synthesised in the adrenal gland
steroid hormone- chemical messengers secreted into the blood
e.g. the effects of catecholamines on vascular tone
* Important in homeostasis e.g. conditioning the body’s
response to stress
where are GCs made?
secreted by the adrenal gland
what do GCs do?
mediate essential metabolic functions in target tissues
what is the effect of GCs?
what are the 3 main functions of GCs? and how does this occur?
DURING STRESS
what is cortisol also known as ?
hydrocortisone
what family are GCs apart of?
cholesterol family
what else are within the cholesterol family?
steroid hormones
- GCs
- mineralocorticoids
- vitamin D
- androgens (sex hormone)
- oestrogens
- progesterone
what structural properties are within GCs?
lipophilic = cross membranes
bind to cytosolic receptors
how do GCs mediate their effects
alter gene transcription
GC bind to GC receptors that act as TF that determine gene expression applying its effects to distant tissues
what the classifications of steroids?
what determines GC synthesis and secretion?
how can GC cause morning sickness?
high conc of GC’s in the morning = inducing sickness
how does the hypothalamus control GC synthesis?
hypothalamus detects the stress/stimuli
then alerts pituitary gland
pituitary gland releases hormones to endocrine glands
what stimuli is detected by the hypothalamus?
what hormone is released by the pituitary gland?
adrenocorticotropic hormone (ACTH)
anterior
what does ACTH do?
regulate GC synthesis
GC synthesis pathway
Hypothalamus detects signal
CRH released and detected by anterior pituitary
releasing ACTH
ACTH regulated GC synthesis
GC negative response on CRH and ACTH production
what are the three layers of the adrenal gland?
zona glomeruloas
zona fasciculata
zona reticularis
what do the different layers in the adrenal gland produce due to ACTH stimulus?
zona glomeruloas - mineralocorticoids
zona fasciculata - GCs
zona reticularis - androgens
what do mineralocorticoids do?
permissive blood pressure steroid that regulate salt and water retention therefore control volemia
how do GCs transport around the body?
highly protein bound (to CBG 90% and albumin 5%) and
5% free GCs - bioavailable - inducing effect
how does inflammation affect GC transportation?
inflammation = decrease CBG levels = decrease bound CBG and GCs = increase free GCs= increase GC signalling
CBG (Corticosteroid-Binding Globulin)
how is cortisol activated and deactivated?