Steroid Biosynthesis Flashcards
1
Q
- Short term response by adrenal gland involves _ that release catecholamines (NE and EPI)
- Long term response by adrenal gland involves _ that release glucocorticoids and mineralcorticoids
A
- Nerve Impulses
- Steroid Hormone Signaling
2
Q
- Steroid hormones are derived from _
A
- Cholesterol
3
Q
- _ is a precursor to many steroid hormones
A
- Progesterone
4
Q
- Corticosteroids
- Sex hormones
A
- Aldosterone and Cortisol
- Testosterone and Estradiol
5
Q
- Before cholesterol is converted to progesterone, it is converted to pregnenolone via _ enzyme
- This enzyme is found in _ tissue
- Catalyzes the first rate limiting step
- _ regulated by ACTH
A
- Desmolase/CYP11A1/CytochromeP450
- steroid producing (adrenal, testes, ovary, placenta)
- ACTH
6
Q
- ACTH stimulates release of _ from the adrenal cortex
- This feeds back to inhibit CRH release from the hypothalamus and ACTH from the anterior pituitary
A
- Cortisol
7
Q
- Short term action of ACTH (seconds)
A
- Stimulates lipoprotein uptake into cortical cells
- Increases bioavailability of cholesterol in the adrenal cortex
8
Q
- What are the long term effects of ACTH (hours)?
A
- Increased transcription of genes coding for steroidogenic enzymes:
- P450
- Steroid 11 beta hydroxylase
- E- transfer proteins
9
Q
- ACTH and Cancer
A
- In cancer:
- cortisol production is uncoupled from ACTH
- Stim of ACTH is no longer required to activate PKA and make cortisol
10
Q
-
Progesterone
- Receptor
- Action
A
- Binds and activates Progesterone Receptor
- Gestation support hormone
11
Q
-
Cortisol
- Receptor
- Action
A
- Binds and activates glucocorticoid receptor
- Increaes gluconeogenesis and blood pressure
- Anti-inflammatory (EX: Dexmethasone-GR receptor agonist used to treat inflammation)
12
Q
-
Aldosterone
- Receptor
- Action
A
- Binds and activates mineralcorticoid receptor (MR)
- Increases Na+ and H2O retention
- Raises blood pressure
Synthesized in adrenal glands
Distributed to kidney tubules, colon, and parotid
Increases Na+/H2O retention, K+ excretion and blood pressure
13
Q
-
Estradiol
- Receptor
- Action
A
- Binds and activates estrogen receptor alpha
- Female sex development
- Maintenance of bone structure
14
Q
-
Testosterone
- Receptor
Action
- Receptor
A
- Binds and activates androgen receptor
- Male sex hormone
Synthesized in adrenal glands, ovaries, and testes
Distributed to primary and secondary reproductive organs and muscles
Mediates spermatogenesis, secondary male characteristics, bone maturation, and virilization
15
Q
- Normal term infants versus premature infants and production of glucocorticoids
A
- Normal term infants:
- Burst of glucocorticoids during delivery stimulates production of surfactant and alters lung structure
- Premature infants:
- Process is defective-can lead to infant respiratory distress syndrome
- Prevented by giving mother glucocorticoids