Steroid Hormones

Question 1

Steroid biosynthesis

Answer 1

Synthesized from cholesterol

Question 2

Gonadotropin-releasing hormone (GnRH)

Answer 2

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

Question 3

Luteinizing hormone and follicle-stimulating hormone in females

Answer 3

Regulate the menstrual cycle

Question 4

How menstrual cycle works

Answer 4

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

Question 5

How birth control works

Answer 5

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

Question 6

Luteinizing hormone and follicle-stimulating hormone in males

Answer 6

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

Question 7

Most active of estrogens

Answer 7

Estradiol (contains phenol)

Question 8

Estrogen biosynthesis

Answer 8

Synthesized from androstendione or testosterone via aromatase

Question 9

Selective estrogen receptor modulators

Answer 9

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

Question 10

Progestins

Answer 10

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

Question 11

Testosterone

Answer 11

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

Question 12

5 alpha reductase

Answer 12

Turns testosterone into 5 alpha-dihydrotestosterone (DHT)

Blocking this enzyme is an approach for controlling androgen action

Question 13

Anabolic androgenic steroids

Answer 13

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

Question 14

Most important hormonal steroids

Answer 14

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

Question 15

Biosynthesis of aldosterone and hydrocortisone

Answer 15

Synthesized from pregnenolone through a series of hydroxylations

Question 16

Glucocorticoids

Answer 16

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