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Biochem Quiz #2 (part 1/2 for exam #2) > Cell Signaling Pathways: Steroid Hormones 9/15/21 > Flashcards

Cell Signaling Pathways: Steroid Hormones 9/15/21 Flashcards

1
Q

steroid hormones can be grouped into different types, based on receptors binding to what (7)?

A

glucocorticoids, mineralocorticoids, androgens, estrogens, progesterones, thyroid, and vitamin D3

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2
Q

what are steroid hormones synthesized from?

A

cholesterol

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3
Q

what are steroid hormones?

A

are lipids, which are fat soluble.

can pass freely by diffusion through biological membranes and enter cells without a specific transporter mechanism.

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4
Q

how do steroid hormones circulate in blood?

A

bound to specific binding or carrier proteins rather than circulating free

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5
Q

what are the two routes that steroids exert biological effects?

A
  1. slower “genomic” response (hours and longer)

2. faster “nongenomic” mechanism (minutes).

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6
Q

what mediates genomic actions hours to days?

A

nuclear receptor

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7
Q

Membrane-associated receptors

A

activate intracellular signaling pathways to bring about nongenomic actions of steroid hormones.

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8
Q

Biosynthesis of aldosterone

A

cholesterol->pregnenolone-> progesterone->deoxycortocosterone->corticosterone->aldosterone

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9
Q

Biosynthesis of cortisol

A

cholesterol->pregnenolone-> progesterone-> deoxycortisol->cortisol

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10
Q

Biosynthesis of dihyrotestosterone (DHT)

A

cholesterol->pregnenolone-> DHEA-> androstenedione->testosterone-> DHT

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11
Q

Biosynthesis of estradiol (2 ways)

A

cholesterol->pregnenolone-> progesterone-> androstenedione->testosterone*-> Estradiol

OR

-> androstenedione->estrone*-> Estradiol

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12
Q

Plasma proteins bind and facilitate the circulation of lipid (hydrophobic) hormones (3)

A
  1. Retinoic acid binding protein binds retinoic acid
  2. Sex hormone binding globulin binds testosterone and estradiol
  3. Vitamin D binding protein binds vitamin D
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13
Q

another word for estrogen

A

estradiol

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14
Q

lipid hormones bind to nuclear steroid\thyroxine receptor superfamily (3)

A
  1. Cholesterol -> cortisol
  2. Metabolite of Vitamin A1->retinoic acid
  3. synthesized from tyrosine & residues in thryoglobin -> thyroxine
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15
Q

cortisol is synthesized from?

A

cholesterol

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16
Q

Retinoic acid

A

a metabolic derivative of vitamin A that has powerful effects on limb bud development in embryos and skin renewal in adult mammals.

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17
Q

Thyroxine

A

synthesized from tyrosine residues in the protein thyroglobulin in the thyroid gland.

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18
Q

what are the 2 pathways in the simple model of steroid hormone action?

A
  1. genomic (classical)

2. nongenomic

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19
Q

overall domain structure of nuclear steroid receptors

A

variable region (amino acid identity)=DNA binding domain=hormoned binding domain

=: linked

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20
Q

Response element

A

characteristic nucleotide sequences of the DNA sites that bind several major nuclear receptor

21
Q

where are glucocorticoids synthesized?

A

adrenal cortex

22
Q

glucocorticoids

A

(glucose + cortex + steroid) derives from its role in the regulation of the metabolism of glucose; Bind to specific receptor and stimulate transcription

23
Q

primary functions of glucocorticoids

A

increase blood sugar through gluconeogenesis, suppress the immune system, and aid the metabolism of fat, protein, and carbohydrate. It also decreases bone formation by causing osteocyte apoptosis (or autophagy at lower doses) as a side effect.

24
Q

how can glucocorticoids be used?

A

in low doses in adrenal insufficiency

25
Q

how are glucocorticoids used in higher doses?

A

oral or inhaled; to suppress various allergic, inflammatory, and autoimmune disorders. Inhaled glucocorticoids are the second-line treatment for asthma.

26
Q

how can glucocorticoids be administered?

A

post-transplant immunosuppressants to prevent cute transplant rejection and the graft-versus-host disease

27
Q

how is glucocorticoid regulated?

A

corticotrophin releasing hormone by nerves in the hypothalamus ultimately stimulating production of ACTH which acts on the adrenal cortex to produce and release cortisol

28
Q

osteoporosis

A

a skeletal disorder characterized by compromised bone strength predisposes in a person to an increased risk of fracture

29
Q

osteoporosis results in

A 
- 1.5 Million Bone Fractures Annually Including
Hip Fractures
Vertebral Fractures
Wrist and Other Fractures 
- Annual Consequences of Hip Fractures
24% will die from complications
25% will require long-term care
30
Q

Estrogen Effect on Bone Mineral Density (BMD) and fractures

A
  • Change in BMD at menopause

- BMD decrease over tiem

31
Q

Shared risk factors for osteoporosis and periodontitis

A

age, genetics, hormone change, smoking, calcium, Vitamin D

32
Q

post-mendopausal osteoporsis

A

estrogen withdrawal, bone resorption, loss of trabecular strucutre, loss of skeletal strength, fracture

33
Q

Types of androgens

A
  • Dehydroepiandrosterone (DHEA)
  • Androstenediol
  • Androstenedione
  • Testosterone (T)
  • 5α-Dihydrotestosterone (DHT)
34
Q

clinical use of androgens

A
  • Male androgen insufficiency
  • Treatment of children with growth failure
  • Bone marrow stimulation in diseases resulting in hypoplastic or aplastic anemia.
  • Masculinizing hormone therapy
35
Q

Anabolic steroids used for?

A

sed therapeutically to induce male puberty and treat chronic wasting conditions such cancer and AIDS.

36
Q

Anabolic steroids risks

A

harmful changes in cholesterol levels, acne, high blood pressure, liver damage, and changes in left ventricle of the heart.

37
Q

Anabolic steroids adverse effects

A

significant psychiatric symptoms including aggression and violence, mania, and less frequently psychosis and suicide have been associated with steroid abuse (WWE wrestlers, weight lifters).

38
Q

Anabolic steroids are familiar to what?

A

testosterone

39
Q

Androgen insensitivity syndrome

A

mutations in androgen receptor (testosterone) cause absence of binding or qualitative/quantitative changes leading to testicular feminization or Reifenstein syndrome

40
Q

Estrogen receptor

A

Various ERα point mutations have been found in breast cancer, endometrial cancer and psychiatric diseases.

“Famous” case reported in 1994 of a 28-year-old male with incomplete epiphyseal closure, was 80.3 inches tall (still growing). Found to have a mutation in ESR1 gene. Case demonstrated the importance of estrogen in males.

41
Q

Generalized glucocorticoid resistance

A

effect in glycocorticoid receptor; mutation in ligand binding domain of GR-alpha. Presented with history of fatigue, anxiety, hyperandrogenism, and hypertension

42
Q

Vitamin D receptor

A

Hereditary Vitamin D Resistant Rickets, Alopecia, Intervertebral Disc Disease, Leprosy

43
Q

Nongenomic Steroid Hormone Action

A

a response to receptor binding that does not initially influence gene expression, but involves signaling cascades (which may or may not result in gene expression changes).

44
Q

types (3) of steroid hormone receptors as targets for drugs

A
  1. agonists
  2. antagonists
  3. topical issues
45
Q

agonists

A

bind to a steroid hormone receptor and trigger signaling pathways characteristic of the original hormone
ex. dianabol

46
Q

antagonists

A

bind to the nuclear hormone receptors but do not trigger signaling pathways (like competitive inhibitors).
ex. tamoxifen and raloifene

47
Q

Topical issues

A

Environmental and food chemicals which bind to estrogen and testosterone receptors weakly.
ex. bisphenol, phytoestrogen

48
Q

Genomic Steroid Hormone Action

A

interactions of the steriod hormones with cytoplasmic or nuclear receptors. Hormone-receptor complexes bind to specific sequences in the DNA (hormone response elements, HRE) to effect gene expression

Biochem Quiz #2 (part 1/2 for exam #2) (4 decks)

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