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DEMS Unit 3 > Intro to Repro system > Flashcards

Intro to Repro system Flashcards

1
Q

3 major categories of sex steroids

A
  1. Progestins
  2. Androgens
  3. Estrogens
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2
Q

Extra-gonadal tissues that secrete various sex steroids

A
  1. Placenta
  2. Dermis
  3. Adrenal glands
  4. Adipose tissue
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3
Q

Which is a glucocorticoid and which is mineralocorticoid?
Cortisol
Aldosterone

A

Cortisol: Glucocorticoid

Aldosterone: mineralocorticoid

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4
Q

How many carbons in:

Cholesterol

A

Cholesterol: 27 C

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5
Q

Gonadal cells (Ie: Leydig cells) cans synthesize cholesterol via which 2 ways?

A
  1. De novo from co-enzyme A

2. Derive cholesterol form LDL in circulation

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6
Q

RLS in steroid synthesis involves which enzyme?

A

20, 22 desmolase (SCC Enzyme) in mitochondria
- this is the first step of converting Cholesterol (27C) to Pregnenolone (21C) in the mitochondria

*pregnenolone is then converted into all other sex steroids

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7
Q

Cholesterol is converted to ______ in the first step of steroid synthesis. ______ is then converted into all other sex steroids.

A

Pregnenolone (21C)

Pregnenolone (21C)

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8
Q

Progestins

  • how many carbons?
  • Which hormones?
  • Can be precursor for production of what?
A

(yellow box)
4 progestins - all 21 Cs

(1) Pregnenolone →
(2) 17a-Hydroxypregnenolone OR!!
(3) Progesterone → which can get converted to
(4) 17a-Hydroxyprogesterone

Can be precursor for aldosterone and cortisol by adrenal glands

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9
Q

How many carbons are in aldosterone and cortisol?

A

21Cs

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10
Q

What are the major circulating progestins in males and females?

A

Females: progesterone

Males:
17a-Hydroxyprogesterone

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11
Q

Good marker for late-onset congenital adrenal hyperplasia

A

17-hydroxy progesterone

discussed in other lecture

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12
Q

Progestins affect almost all tissues in the body, most notably which ones?

A
  • the exact same 3 as Estrogens:
  1. uterus
  2. ovaries
  3. breasts
  • growth and development of the tissues and organs related to ovulation, menses, pregnancy, and lactation.
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13
Q

How many carbons are in androgens? Where does it come from?

What are the major androgens that are synthesized in the human body?

A

19C

Derived from cholesterol via pregnenolone
(same as estrogen)

  1. testosterone
  2. dehydroepiandrosterone (DHEA)
  3. DHEA-S
  4. DHT
  5. Androstenedione

*note that estrogen is 18C

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14
Q

Where is the majority of testosterone produced in males?

A

Males:

  • 95%: Leydig cells in testes
  • 5%: adrenal cortex
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15
Q

Where is the majority of DHEA and DHEA-S produced?

A

Adrenal cortex

- excellent marker of adrenal androgen activity

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16
Q

What is the precursor for ovarian estradiol production by the GRANULOSA CELLS?

A

Androstenedione from the theca cells in the ovaries

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17
Q

Enzyme that converts Testosterone to DHT

A

5 a-Reductase
(mainly in testosterone target cells)

*DHT is 30-50x more active and cannot be converted to estrogens

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18
Q

Do androgens have significant effects on the growth of the reproductive system? What about testosterone?

A

Androgens No

Testosterone yes
- affects almost all tissues in the body

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19
Q

Difference between androgenic and anabolic effects of testosterone

A
  1. Androgenic:
    impacts growth and dev of internal and ext genitalia
    - dev of 2ndary sex char, spermatogenesis, sexual fantasy and libido
    - stuff you know
  2. Anabolic:
    Growth promoting effects on somatic tissues (BONE AND MUSCLE)
20
Q

What are the key feedback inhibitors for:

  1. Hypothalamic-Pituitary-ovarian axis
  2. Hypothalamic-Pituitary-testicular axis
A
  1. Progesterone and estradiol

2. Testosterone

21
Q

How many carbons are in Estrogen? What is it derived from?

A

18C

Cholesterol via pregnenolone
same as androgens
- 2 ex of estrogens: estrone, estradiol

22
Q

How are estrogens produced from pregnenolone? What enzyme is involved in that final conversion?

A 
Cholesterol →
Pregnenolone →
Progestins →
Androgens →
Estrogens (via aromatase)
23
Q

Estrogens:
E1
E2
E3

Names and which one is most potent

A

E1: estrone
E2: estradiol
E3: estriol

*one, two, three OH groups

E2 is most potent, E3 is least

24
Q

Where is estradiol produced in males and females

A

Males:
Seroli cells of testes

Females:
Granulosa cells of ovary

25
Where is estrone (E1) and Estriol (E3) produced?
E1: adipose tissue E3: important placental product
26
Why is pulsatile secretion of GnRH the key to physiologic stimulation of the anterior pituitary?
Constant administration of GnRH actually suppresses the pituitary response
27
When do FSH and LH reach their peaks?
Shortly before ovulation
28
LH and FSH stimulate the production of which hormones? | Where do they work?
Sex steroids - negative feedback control on hypothalamus and pituitary Inhibit - neg feedback control on pituitary *at midcycle, estradiol also exerts pos feedback mech on pit gland → FSH + LH surge
29
Two imp cells in testis + ovary
Testis: - Leydig - Sertoli Ovary: - Theca - Granulosa * Male Leydig and female Theca are interstitial cells and are similar * Sertoli + granulosa cells are similar
30
Things that Male Leydig and female Theca are interstitial cells and share
- Able to make androgens + progesterone in presence of LH secretion/rcptrs - Unable to make estrogens due to absence/lack of aromatase (fxn of sertoli and granulosa cells)
31
Things that Male Sertoli and female Granulosa cells have in common
Able to make inhibin in presence of FSH receptors Able to convert androgens into estrogens due to presence of aromatase
32
How does LH stimulate the rate limiting conversion of cholesterol into pregnenolone?
1. Increasing the amt of desmolase | 2. Enhancing the affinity of desmolase for cholesterol
33
Spermatogenesis requires which hormones
``` LH FSH Leydig cells Sertoli cells Testosterone ```
34
Sertoli cells are organized into tubular epithelium known as ________. It is supported by the presence of _____ between sertoli cells.
Seminiferous tubules Tight gap jxns *seminiferous tubules are responsible for maturation of gametes
35
Effects of FSH binding to Sertoli cells
1. Increased production of androgen binding protein 2. Enhanced conversion of testosterone (from Leydig cells) into estradiol 3. Production of Inhibin *sertoli cells are the primary source of inhibin in males
36
The gametes and their surrounding granulosa cells are called ________. The _______ follicle matures each month.
Primordial follicles Dominant follicle
37
Oogenesis and ovulation require which hormones and cells?
1. LH 2. FSH 3. Testosterone 4. Estradiol 5. Granulosa cells 6. Theca cells
38
Granulosa cells lack the enzyme which converts progesterone into androgens, well then how the hell do androgens get produced in females?
Progesterone from the granulosa cells diffused to the theca cells → converted to androstenedione → theca cells lack aromatase → androstenedione diffuses back to granulosa cells → conversion to estradiol
39
LH binds to which cells and FSH binds to which cells?
LH binds to Leydig Cells - L → L FSH binds to Sertoli cells - S → S
40
The biological activity of LH and ____ are very similar. So much so, that it is often substituted for LH because it is much more readily available.
hCG *hCG can be used therapeutically to initiate spermatogenesis in azoospermic or oligospermic men
41
FSH leads to the synthesis of _______, which is secreted into the luminal space of the seminiferous tubule, near the developing sperm cells. ________ Helps to keep local testosterone levels high.
Androgen Binding protein (ABP) Androgen Binding protein (ABP)
42
How is FSH involved in converting Testosterone into estradiol in men?
It causes the synthesis of Aromatase. Testosterone diffuses from Leydig cells → Sertoli cells - In Sertoli cells, aromatase converts T into Estradiol
43
4 things that FSH stimulates Sertoli cells to synthesize
1. Androgen binding proteins (ABP) 2. Aromatase 3. Growth factors 4. Inhibins *FSH may also increase the fertility potential of sperm!
44
Which one inhibits LH, which one inhibits FSH: | Testosterone vs Inhibin
Testosterone inhibits pulsatile release of LH - by inhibiting pulsatile release of GnRH Inhibin inhibits FSH secretion (FSH stimulates Sertoli cells to make inhibin, and inhibin "inhibits" FSH secretion)
45
Two immediate precursors for Testosterone and two hormones that can come from Testosterone
Androstenedione or Androstenediol → Testosterone Testosterone → Estradiol or DHT
46
All of the DHEA in male plasma originates from where?
Adrenal glands | - Can test adrenal fxn using DHEA

DEMS Unit 3 (26 decks)

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