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Flashcards in Steroids Deck (50):
1

What are the 5 classes of steroid hormones?

-Glucocorticoids -Mineralocorticoids -Androgens -Estrogens -Progestins

2

Synthesis and secretion of cortisol and aldosterone occur in what?

Adrenal cortex

3

Synthesis and secretion of estrogens and progestins occur in what?

Ovaries and ovarian corpus luteum

4

Synthesis and secretion of testosterone occurs in what?

Testes

5

What is the blood carrier protein used by cortisol?

Transcortin

6

What is the blood carrier protein used by the sex hormones?

Sex hormone-binding protein

7

Hydrophobic steroid hormones can be non-specifically carried by what?

Albumin

8

What molecule is used to transport cholesterol into the mitochondria?

StAR (Steroidogenic acute regulatory protein)

9

What is the regulatory step of cortisol synthesis?

Transport of cholesterol into mitochondria by StAR

10

In the initial reaction of steroid hormone synthesis, cholesterol gets converted to what?

Pregnenolone

11

What is the role of 3-B-hydroxysteroid dehydrogenase?

Oxidizes and isomerizes pregnenolone to progesterone

12

What is the role of Cholesterol Esterase?

Cleaves Cholesterol esters into Cholesterol. (this enzyme is activated by PKA)

13

The rate-limiting step of steroid hormone synthesis requires what two molecules?

-NADPH -O2

14

What is the rate limiting enzyme in steroid hormone synthesis?

Desmolase (aka: Cholesterol Side Chain Cleavage Enzyme CYP 11A1 P450 scc)

15

____________ reactions modify progesterone to other steroid hormones

Hydroxylation

16

Most enzyme (hydroxylases) in steroid biosynthesis are _____________ enzymes

Cytochrome P450-dependent

17

What region of the Adrenal gland releases Aldosterone?

Z. Glomerulosa

18

What region of the Adrenal Gland releases Cortisol?

Z. Fasciculata

19

What region of the Adrenal gland releases androgens (DHEA, Androstenedione)

Z. Reticularis

20

What does ACTH stand for?

Adrenocorticotropic hormone

21

ACTH, through actions of cAMP, stimulate synthesis of what steroid?

Cortisol

22

Angiotensin II/III, through actions of PIP2/IP3/Ca2+, stimulate synthesis of what steroid?

Aldosterone

23

Follicle Stimulating Hormone (FSH), through action of cAMP, stimulates synthesis of what steroid?

Estradiol

24

Luteinizing Hormone (LH), through action of cAMP, stimulates synthesis of what steroid?

Progesterone and Testosterone

25

In general, what are the actions of cortisol once released?

-Stimulate gluconeogenesis -Anti-inflammatory action -Protein breakdown in muscle.

26

How does cortisol counteract the action of insulin?

Cortisol leads in general to degradation of muscle protein

27

What are the 3 ways cortisol is involved in reducing inflammation?

- Inhibits Phospolipase A2 -Less arachidonic acid available for synthesis of eicosanoids (inflammatory mediators) -Inhibits induction of COX-2

28

What is the role of aldosterone?

-Raises blood pressure and fluid volume -Increases Na+ uptake

29

What are the two main androgens?

Dehydroepiandrosterone (DHEA) Androstenedione

30

What type of cells contain LH receptors, which increases cAMP and PKA resulting in testosterone synthesis?

Leydig Cells

31

What is produced by Sertoli Cells?

Dihydrotestosterone (DHT)

32

Regarding steroid receptor mechanism of signal transduction, what are HREs?

-Hormone response elements. -Upon binding by Receptor Protein (Rec) activated by hormone, HREs regulate transcription of adjacent genes, increasing or decreasing rate of mRNA formation.

33

What causes Congenital Adrenal Hyperplasias? (CAH)

Deficiency of: - 3-B-hydroxysteroid dehydrogenase - 17-alpha-Hydroxylase

34

What does 3-B-hydroxysteroid dehydrogenase deficiency result in?

-Vitrually no glucocorticoids, mineralocorticoids, active androgens, or estrogens

35

What does 17-alpha-Hydroxylase deficiency result in?

Virtually no sex hormones or cortisol are produced

36

17-alpha-Hydroxylase is abbreviated as

CYP17

37

Mineralocorticoids and glucocorticoids are virtually absent from deficiency of what?

Classic form of 21-alpha-Hydroxylase deficiency

38

Mineralocorticoids and glucocorticoids are deficient from deficiency of what?

Non-classic form of 21-alpha-Hydroxylase deficiency (Note: classic form stems from almost complete absence of enzyme)

39

What is the most common form of Congenital Adrenal Hyperplasia?

21-alpha-Hydroxylase deficiency

40

Overproduction of Androgens leads to masculinization of external genitalia in females and early virilization in males results from deficiency of what enzyme?

21-alpha-Hydroxylase deficiency

41

Decrease in serum cortisol, aldosterone, and coticosterone results from deficiency of what enzyme?

11-B-Hydroxylase deficiency

42

How does 11-B-Hydroxylase deficiency cause low-renin hypertension?

Increases production of deoxycorticosterone, causing fluid retention . This hormone supresses fluid retention.

43

Deficiency of what two enzymes leads to masculinization and virilization?

11-B-hydroxylase 21-alpha-hydroxylase

44

What syndrome describes the results of hypercortisolism?

Cushings Syndrome

45

Cushings syndrome is due to what?

High cortisol concentration and low ACTH concentration in plasma (high cortisol in urine)

46

Glucocorticoid excess, as seen in Cushing's syndrome, leads to...

Protein loss characteristic fat distribution

47

What is Addison's disease?

Primary adrenal cortical insufficiency

48

Addison's disease is caused by?

-Adrenal cortex atrophy due to diease -Mostly by autoimmune destruction

49

Addison's disease is characterized by?

Low Aldosterone and cortisol levels High ACTH

50

Draw out the synthesis of steroid hormones

(Memorize this diagram!!!)

A image thumb