Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Block 3 Week 6 Meg > Blomquist: Steroid Hormones > Flashcards

Blomquist: Steroid Hormones Flashcards

1
Q

(blank) is the precursor to steroid hormones

A

cholesterol

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

C21: produced directly from cholesterol, the precursor molecule for all C18, C19 and C21 steroids. Not a hormone by itself.

A

pregnenolone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

C21: a progestagen, produced directly from pregnenolone and secreted from the corpus luteum, responsible for changes associated with luteal phase of the menstrual cycle, differentiation factor for mammary glands

A

progesterone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

C21 steroid hormones are called (blank)

A

pregnanes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

C19: an androgen, male sex hormone synthesized in the testes, responsible for secondary male sex characteristics, produced from progesterone

A

testosterone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

C21: dominant glucocorticoid in humans, synthesized from progesterone in the zona fasciculata of the adrenal cortex, involved in stress adaptation, elevates blood pressure and Na+ uptake, numerous effects on the immune system

A

cortisol

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

C21: the principal mineralocorticoid, produced from progesterone in the zona glomerulosa of adrenal cortex, raises blood pressure and fluid volume, increases Na+ uptake

A

aldosterone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

C19 steroid hormones are called (blank)

A

androstanes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

C18 steroid hormones are called (blank)

A

estranes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

C18: an estrogen, principal female sex hormone, produced in the ovary, responsible for secondary female sex characteristics

A

estradiol

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What changes are most prominent in distinguishing estradiol?

A

methyl group lost at C19; the A ring is aromatic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What changes are most prominent in distinguishing testosterone?

A

Loss of C20 and C21

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is one thing that distinguishes estradiol in a 3D picture?

A

A ring is aromatic and points UP whereas in other steroid hormones it points down

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Modifications to cholesterol that occur to make steroid hormones

A 
Cleavage of 6C side chain
Delta 4-5 double bond
Aromatization of A group
Formation of a ketone
Hydroxylations
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

(blank) are extensively used in steroid hormone biosynthesis

A

Cytochrome P-450s

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

A superfamily of heme-containing membrane bound proteins

A

cytochrome P-450s

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Where are cyto P-450s generally found? What is their most common reaction?

A

in the smooth ER of the liver and lungs and in the mito; hydroxylation reaction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is the general equation for action of a cyto P-450?

A

Substrate-H + O2 + NADPH + H+ –> Substrate-OH + H20 + NADP+

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Cholesterol 6C side chain cleavage enzyme
One of the most essential P450s
Mutations usually fatal in utero

A

CYP11A1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

CYP11A1 is the cyto P-450 that takes cholesterol to (blank)

A

pregnenolone (all steroids derived from pregnenolone)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

All steroids go through (blank) and undergo a series of (blank) reactions

A

pregnenolone; hydroxylase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Which two steroid hormones have the 11-OH group?

A

corticosterone and aldosterone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

To form estradiol from testosterone, what must occur?

A

aromatase system forms an aromatic ring (and removal of a methyl group)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

The hormonal cascade refers to synthesis and secretion of specific releasing hormones by (blank) neurons. Releasing hormones stimulate the synthesis and release of tropic hormones from the (blank). Tropic hormones increase the synthesis and secretion of specific hormones by (blank).

A

hypothalmic neurons; anterior pituitary; target endocrine glands

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Protein hormones bind to cell membrane receptors and transmit signal across membranes. List some second messengers. Many second messengers activate protein kinases.

A

cAMP, cGMP, IP3, DAG

26
Q

The adrenal cortex produces (blank), (blank), and (blank)

A

aldosterone
cortisol
androgens

27
Q

(blank) cells of male testes produce testosterone; female ovaries produce (blank) and (blank); steroid hormones are transported via specific (blank) to protect them from degradation

A

Leydig; estrogen, progesterone; plasma proteins

28
Q

List two releasing hormones from the hypothalamus and the hormones that they “release” from the pituitary

A

CRH from hypothal–>ACTH from pituitary–>cortisol

GnRH from hypothal–>LH and FSH–>LH: progesterone and testosterone FSH: estradiol

29
Q

Releasing hormones are released at the (blank) level, while anterior pituitary hormones are released at the (blank) level

A

nanogram; microgram

30
Q

Cortisol

What’s the steroid producing cell? What’s its signal? What’s its second messenger? What’s its signal system?

A

adrenal (zona fascicula); ACTH; cAMP, PI cycle, Ca; hypothalmic-pituitary cascade

31
Q

Aldosterone

What’s the steroid producing cell? What’s its signal? What’s its second messenger? What’s its signal system?

A

adrenal (zona glomerulosa); angiotensin II; PI, Ca; reno-angiotensin system

32
Q

Testosterone

What’s the steroid producing cell? What’s its signal? What’s its second messenger? What’s its signal system?

A

Leydig cell; LH; cAMP; hypothalmic-pituitary cascade

33
Q

Estradiol

What’s the steroid producing cell? What’s its signal? What’s its second messenger? What’s its signal system?

A

ovarian follicle; LH; cAMP; hypo-pituitary cascade

34
Q

Progesterone

What’s the steroid producing cell? What’s its signal? What’s its second messenger? What’s its signal system?

A

corpus luteum; LH; cAMP; hypo-pituitary cascade

35
Q

Vit D

What’s the steroid producing cell? What’s its signal? What’s its second messenger? What’s its signal system?

A

kidney; PTH; cAMP; sunlight, plasma calcium

36
Q

Give an overview of hormonal stimulation of steroid hormone biosynthesis

A

Peptide hormone binds to receptor, confirmational change in protein, GDP to GTP, which binds to AC, increases cAMP, leads to activation of PKA, phosphorylates cholesterol esterase, frees cholesterol from vesicles, StAR protein allows for its uptake into the mito matrix, CYP11A1 can then make modifications and release the hormone into the bloodstream

37
Q

Discuss the activation of ACTH on adrenal fasciculata cells

A

ACTH binds, activates a G protein, activates cAMP, activates PKA, PKA releases cholesterol from vesicles, cholesterol transported to mito via StAR, side chain cleavage and other steps in cortisol production occur here, then it is released into the cytosol and into the bloodstream.

38
Q

(blank) plays a minor role in aldosterone regulation

A

IP3 signaling system

39
Q

7-Dehydrocholesterol is synthesized in the liver and is found in the skin. It is taken to previtamin D via (blank), then the ring spontaneously opens, and forms Vit D. T

A

sunlight, UV radiation

40
Q

What is the major effect of vitD?

A

To stimulate Ca+ and phosphate absorption from the lumen. Also increases Ca+ pump molecules and calbindins

41
Q

How are steroid hormones transported in the blood?

A

Corticosteroid binding globulins
Sex hormone binding globulin
Androgen binding protein
Albumin

42
Q

Cortisol binds primarily to corticosteroid binding a2-globulin (transcortin). About 15 % of cortisol is
(blank) cortisol and this is what crosses cell membranes and binds to cortisol receptors in cells

A

free

43
Q

What percentage of testosterone is bound to sex hormone binding protein?
What percentage of estrogen is bound to sex hormone binding protein?

A

65%; 60%

44
Q

Androgen binding protein is also called testosterone-estrogen binding globulin: this protein helps maintain a high level of (blank) within testes and seminal fluid and is important for development and maturation of (blank)

A

testosterone; sperm

45
Q

What does progesterone bind to primarily?

A

transcortin and albumin

46
Q

Subfamily of receptors including steroid hormone, Vit D, thyroxine, and retinois (Vit A) receptors

A

nuclear receptor subfamily

47
Q

3 important domains on nuclear receptors

A

poorly conserved transcription-activation domain
highly conserved DNA binding domain
ligand binding domain

48
Q

Steroid receptors bind to DNA as (blank); they increase or decrease (blank)

A

homodimers; transcription

49
Q

T/F: Steroid hormones can travel THROUGH cell membrane, unlike peptide hormones which cannot. Some glucocorticoid receptors are free in the cytoplasm and are transported to the nucleus when bound by their hormone; others steroid receptors are already in the nucleus when unbound.

A

True

50
Q

This domain on the steroid receptor protein is variable

A

trx activation domain

51
Q

This domain on the steroid receptor protein contains zinc fingers

A

DNA binding domain

52
Q

This domain on the steroid receptor protein is at the end and is specific to what it binds

A

ligand binding domain

53
Q

(blank) and (blank) have nuclear receptors in the same family as steroid receptors

A

retinoic acid; T3

54
Q

Caused by adrenal insufficiency

A

Addison’s disease

55
Q

Caused by increased cortisol secretion due to a tumor on the pituitary gland

A

Cushing syndrome

56
Q

Result from loss of function in one of several genes involved in adrenal corticol steroid hormone synthesis. Results in accumulation of of steroid intermediates proximal to the defective enzyme. Common forms result from loss of function of
21-hydroxylase or 11-hydroxylase.

A

Congenital adrenal hyperplasias (CAH)

57
Q

lipoid congential adrenal hyperplasia
adrenal and gonadal steroid production severly impaired
What causes this?

A

non-functional StAR

58
Q

DNA binding domains have 8 cys groups of 4 tetrahedrally coordinately binding 2 Zn+2 ions; many have (blank) on DNA that have two half site sequences 5’ AGAACA 3’ for steroid receptors

A

hormone response elements

59
Q

Name a C18 steroid. Name a C19 steroid. Name 3 C21 steroids.

A

estrogen; testosterone; progesterone, cortisol, aldosterone

60
Q

Where is the unbound receptor for glucocorticoids found? When does it dimerize and move to the nucleus?

A

in the cytoplasm; when the steroid hormone binds

61
Q

What distinguishes progesterone from pregnenolone?

A

double bond moves from C5 to C4

62
Q

Also called testosterone-estrogen binding globulin; helps maintain a high level of testosterone in the seminferous tubules

A

androgen binding protein

Block 3 Week 6 Meg (7 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions