Lecture 10: Biosynthesis of Steroid Hormones Flashcards

1
Q

modes of cell-cell communication

A

-juxtacrine signaling
-endocrine signaling
-paracrine signaling
-synaptic/neuronal signaling
-autocrine signaling

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2
Q

Juxtacrine signaling

A

-direct physical contact

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3
Q

Endocrine signaling

A

-travels far through blood to target organ
-low concentration
-high affinity receptors
-minutes to hours

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4
Q

Paracrine signaling

A

-travels short distance
-affects neighboring cells
-rapid and localized communication

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5
Q

synaptic/neuronal signaling

A

-neurotransmitter
-short distance
-high local concentration
-dissociate rapidly
-millisecond termination

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6
Q

autocrine signaling

A

-made and functions in same cell

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7
Q

Steroid hormone structure

A

-made from cholesterol
-planar, rigid, hydrophobic
-tight binding to receptors
-low concentrations in body
-bound to serum carrier proteins

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8
Q

Steroid hormone action

A

-diffuse through cell membrane
-bind steroid hormone receptor
-regulate transcription of a specific set of genes

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9
Q

Classes of steroid hormones

A

-sex and progestational hormones
-adrenocortical hormones

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10
Q

sex and progestational hormones

A

-progesterone
-17B-estradiol
-testosterone

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11
Q

Adrenocortical hormones

A

-Cortisol
-Aldosterone

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12
Q

structure of steroid hormones

A

-share 4 rings of cholesterol

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13
Q

Steroid receptors

A

-intracellular
-bind steroid hormones
-regulate transcription of specific set of genes
-belong to nuclear family

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14
Q

Steroid receptor structure

A

-DNA-binding domain
-hormone-binding domain

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15
Q

Hormone Responsive Elements (HRE)

A

-specific DNA seq
-binds to active, dimerized steroid receptors
-binds DNA-binding domain
-alters rate of transcription

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16
Q

negative feedback loop?

A

slide 15?

17
Q

Synthesis of steroid hormones

A

-Cholesterol to pregnenolone
-P450

18
Q

Pregnenolone to Aldosterone

A

-Pregnenolone to progeterone
-progesterone to aldosterone (ADRENAL)

19
Q

Pregnenolone to DHEA

A

-17a-hydroxylase (adds -OH)
-17,20-Lyase (=O)

20
Q

I’m not writing all those down

A

SLide 17 like actually

21
Q

17a-hydroxylase deficiency

A

-rare form of congenital adrenal hyperplasia
-mutations in CYP17A1
-overproduction of mineralcoricoids
-deficiency of corticosteroids and sex hormones

22
Q

17a-hydroxylase symptoms

A

-HYPOcortisolism (enlargement of adrenal glands)
-ambiguous genitalia
-hyperaldosteronism (HTN)

23
Q

21-hydroxylase

A

-adds -OH to methyl on progesterone

24
Q

21-hydroxylase deficiency

A

-major form of congenital adrenal hyperplasia
-mutations in CYP21A2

25
Q

21-hydroxylase deficiency symptoms

A

-hypocorisolism
-hypoaldosteronism (hyponatremia can be life threating in infants)

26
Q

21-hydroxylase deficiency premature androgen exposure

A

-ambiguous genitalia in female
-hirsutism
-early epiphyseal closure = short height

27
Q

Synthesis of testosrerone and estradiol location

A

-ovaries and testes
-androstenedione too testosterone
-testosterone to 17B-estradiol
-17,20-Lyase

28
Q

Transport of steroids

A

-by plasma proteins in plasma
-corticod-binding globulin (transcortin)
-sex hormone binding globuling (SHBG)

29
Q

corticoid-binding globulin (transcortin)

A

-transport glucocorticoids and progesterone

30
Q

sex hormone binding globulin (SHBG)

A

-transport testosterone and estradiol

31
Q

Steroid metabolism

A

-in liver
-oxidation, sulfation, gglucoronidation to soluble forms

32
Q

Steroid excretion

A

-in bile (estrogen)
-in urine (progesterone, androgen, glucocorticoids)

33
Q

Aminoglutethimide

A

-inhibits aromatase and P450scc
-used to block steroid production in some hormone-dependent tumors (breat/prostate)

34
Q

Ketoconazole

A

-antifungal at lower concentrations (block ergosterol synthesis)
-inhibits P450scc, 17a-hydroxylase, and 11B-hydroxylase
-can treat hyperglucocorticoid states (cushing’s syndrome)
-may cause toxic side effects

35
Q

nonselective steroidgenesis inhibitor drugs

A

-aminoglutethimide
-ketoconazole