Steroidogenesis Enzymes Flashcards
HMG-CoA reductase
Acetyl-CoA —> cholesterol
P450SCC
Cholesterol —> pregnenolone
P450C17
pregnenolone –> DHEA
3β-HSD
pregnenolone –> progesterone
P450C21
progesterone –> intermediate for cortisol, corticosterone, and aldosterone
P450C11
nonactive intermediate –> cortisol or corticosterone
P450ALDO
corticosterone –> aldosterone
P450ARO
testosterone –> 17β-estradiol
5α-reductase
testosterone –> DHT
1α-reductase
25-hydroxycholecacalciferol –> 1,25-hydroxycholecalcalciferol (active vitamin D3)
Where is vitamin D3 synthesized?
kidneys
Where are the glucocorticoids (cortisol and corticosterone) synthesized?
adrenal cortex
Where are the adrenal androgens (mainly DHEA) synthesized?
adrenal cortex (Δ5 pathway)
Where are mineralocorticoids (aldosterone) synthesized?
adrenal cortex
Where are gonadal androgens (testosterone and DHT) synthesized?
gonads
Where are estrogen (17β-estradiol) and progesterone produced?
gonads & placenta
Where is dopamine produced?
parvocellular neurons of the arcuate nucleus (hypothalamus)
Where is norepinephrine produced?
SNS postganglionic neurons
Where is epinephrine produced?
adrenal medulla
What are catecholamines?
dopamine, NE, epi
Where is melatonin produced?
pinealocytes
Where is thyroid hormone produced?
thyroid gland
Where are peptide hormones produced?
every endocrine organ except the adrenal gland
Examples of amine hormones
melatonin, catecholamines, thyroid hormones
