Steroid Hormones Flashcards Preview

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Flashcards in Steroid Hormones Deck (16):
1

Steroid biosynthesis

Synthesized from cholesterol

2

Gonadotropin-releasing hormone (GnRH)

Regulates release of luteinizing hormone, follicle-stimulating hormone, and chorionic gonadotropin (only expressed during pregnancy)

3

Luteinizing hormone and follicle-stimulating hormone in females

Regulate the menstrual cycle

4

How menstrual cycle works

FSH and LH cause increase in estradiol levels
Increase in estradiol causes LH to surge
LH surge triggers ovulation

5

How birth control works

Keeps levels of estradiol constant, preventing spike in LH and thus ovulation
Suppresses production of LH, FSH, or both
Attempts to mimic the body's natural estrogen/progestin levels throughout the cycle

6

Luteinizing hormone and follicle-stimulating hormone in males

LH: stimulation of testosterone synthesis in testes
FSH: stimulation of production of proteins required for sperm maturation

7

Most active of estrogens

Estradiol (contains phenol)

8

Estrogen biosynthesis

Synthesized from androstendione or testosterone via aromatase

9

Selective estrogen receptor modulators

Tissue-specific estrogenic activity
Agonistic or antagonistic effects, depending on tissue
Example: tamoxifen (estrogen antagonistic action for breast cancer)

10

Progestins

Act in regulation of menstrual cycle (decline in release from corpus luteum sparks start of menstruation cycle)
Pregnancy: suppresses menstruation and prepares for lactation

11

Testosterone

Androgen
Synthesized through pregnenolone, DHEA, or androstenedione
Produced in the testes in response to LH release

12

5 alpha reductase

Turns testosterone into 5 alpha-dihydrotestosterone (DHT)
Blocking this enzyme is an approach for controlling androgen action

13

Anabolic androgenic steroids

Primary use is androgen replacement therapy in men
Also used to relieve bone pain associated with osteoporosis and to treat anemias
Problem: abuse by athletes

14

Most important hormonal steroids

Aldosterone: maintain constant electrolyte balance and blood volume
Hydrocortisone: control carbohydrate, protein, and lipid metabolism

15

Biosynthesis of aldosterone and hydrocortisone

Synthesized from pregnenolone through a series of hydroxylations

16

Glucocorticoids

Increase lipid metabolism and synthesis
Regulate growth hormone gene expression
Anti-inflammatory and immunosuppressive actions (why resistance to these causes arthritis and lupus)
Stimulate glycogen storage by inducing synthesis of glycogen synthase
Used to treat inflammatory conditions, relieve symptoms of allergies, treat asthmatic symptoms