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19 Cards in this Set
- Front
- Back
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Name few androgens
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Testosterone
Dehydroepiandrosterone Dihydrotestosterone |
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Name few estrogens
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17-beta-estrodiol
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Name the hormone that is required for embryo implantation
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Luteinizing hormone:
causes secretion of progesterone from corpus luteum --> maintains uterine endometrium for implantation |
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What are the functions of DHEA?
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- a weak androgen that can be converted into a more potent androgen in extra-adrenal tissue
- important precursor of estrogen in postmenopausal women - inhibitor of G-6-P DH - regulates NAD+ coenzymes |
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What are the functions of aldosterone and cortisol?
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Aldosterone:
- excretion of K+ and retention of Na+ ion via conductance channel - produced in high levels during stress - raises blood pressure and fluid volume Cortisol: - stimulates gluconeogenesis in liver - protein degradation in muscle - mobilization of fatty acids from adipose tissue - helps increase blood glucose through gluconeogenesis |
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What is the role of StAR?
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Steroidogenic acute regulatory (StAR) protein:
- hormone-induced transport protein factor that mediates acute (occurring w/in seconds to mins) regulation of steroid hormone biosynthesis |
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Which is the rate limiting step in steroid biosynthesis?
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side chain cleavage of cholesterol in the mitochondria is the rate limiting step
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What is the role of 5alpha-reductase?
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An enzyme located in the ER that is required for the conversion of testosterone into DHT (dihydrotestosterone)
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Name the enzyme that converts testosterone into estradiol?
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Aromatase (a type of P450 hydroxylase) system in leydig cells
OR via DHEA in follicular cells and mammary glands |
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Name the organ in which aldosterone and cortisol are produced?
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Adrenal glands
aldosterone - zona glomerulosa cortisol - zona fasciculata and zona reticularis |
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Name the most common enzyme in steroid biosynthesis (generic name is sufficient)
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P450-hydroxylases
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Conversion of cholesterol into pregnenolone occurs in _________.
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the mitochondria
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Describe the signaling relay for the secretion of cortisol.
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hypothalamus --CRF (corticotropin releasing factor) --> anterior pituitary --ACTH--> adrenal cortex --> cortisol
cortisol has 2 fates: 1. either act on target tissues like liver, muscle, adipose 2. negative inhibition on hypothalamus, ultimately reducing cortisol release |
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Describe the signaling relay for the synthesis of cortisol and aldosterone.
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Cholesterol --1--> pregnenolone --2--> progesterone --3--> cortisol and aldoesterone
Enzymes: 1. desmolase or 20-22 lyase 2. dehydrogenase and isomerase 3. aldosterone - 3 hydroxylases at carbon 21, 11, 18 cortisol - 2 ER hydroxylases at carbon 17 and 21 and another at 11 |
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Describe the signaling relay for the secretion of aldosterone.
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angiotensinogen --1--> antiogenin I --2--> angiotensin II --3--> angiotensin III ----> adrenal glands --> aldosterone release
Enzymes: 1. renin 2. ACE 3. ACE |
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Describe the signaling relay for the synthesis of estrodiol and progesterone
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Cholesterol --1--> pregnenolone --2--> progesterone --3--> testosterone --4--> DHT --5--> estradiol
Enzymes: 1. desmolase or 20-22 lyase 2. dehydrogenase and isomerase 3. ER enzymes and another cytoplasmic DH 4. 5 alpha-reductase 5. aromatase |
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Describe the signaling relay for the secretion of estrodiol and progesterone
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hypothalamus --GnRH--> anterior pituitary --FSH/LH--> ovary -->
FSH - estradiol LH - progesterone |
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Describe the signaling relay for the synthesis and secretion of angiotensin II and III
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due to hypovolemia (decreased Na+):
kidney (juxtaglomerulosa cells) releases renin angiotensinogen --renin--> angiotensin I --ACE--> angiotensin II --ACE--> angiotensin III |
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What are P450-hydroxylases?
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use molecular oxygen as a substrate, where:
1st oxygen atom is incorporated into the steroidal substrate (as OH) 2nd atom reduced to water molecule Electrons donated by NADPH |
