Endocrinology of the Male Reproductive Tract

Question 0

FSH targets the ___ cells

Answer 0

Sertoli

Question 1

LH targets the __ cells

Answer 1

Leydig

Question 2

Leydig cells produce:

Answer 2

testosterone

Question 3

testosterone feedbacks at the gonadotroph cells to ____ the secretion of LH and FSH, and feedbacks at the hypothalamus to ___ the secretion of GnRH

Answer 3

decrease: LH FSH

decrease GnRH

Question 4

Sertoli cells produce:

Answer 4

sperm

Question 5

spermatogenesis depends on:

Answer 5

FSH and testosterone

Question 6

another action of FSH acting on the Sertoli cell is the production of:

Answer 6

ABP (androgen binding protein)

Question 7

ABP helps ensure:

Answer 7

a large concentration of testosterone within the seminiferous tubules

Question 8

Sertoli cells make their own hormone, ____, which serves as ____

Answer 8

inhibin, a negative feedback signal for FSH, reduces their responsiveness to GnRH, and probably directly inhibits the release of GnRH

Question 9

what accounts for the difference in the pulsatile rate of LH and FSH secretion?

Answer 9

testosterone changes the sensitivity of the cells producing LH
inhibin changes the sensitivity of the cells producing FSH

Question 10

how do glycoprotein hormones from the pituitary work?

Answer 10

it results in the conversion of ATP to cAMP, cAMP activates protein kinases, phosphorylation cascade is going to convert cholesterol to testosterone and estradiol

Question 11

in the blood, testosterone and estradiol mostly get bound up by ___. The rest is bound by ___. Only about __% isn’t bound up

Answer 11

sex steroid binding globulins, albumin and other plasma proteins, 3%

Question 12

testosterone has a __ negative feedback effect on FSH, but a __ negative feedback effect on LH

Answer 12

small, large

Question 13

why is the testosterone effect on FSH so small?

Answer 13

because inhibin is the necessary feedback agent

Question 14

it is the ___ form of testosterone that can interact with target cells

Answer 14

unbound/free

Question 15

what tissues would have testosterone acting directly as testosterone?

Answer 15

penile tissues

Question 16

what tissues convert testosterone to DHT?

Answer 16

hair follicles and prostate, 5-α-reductase

Question 17

what tissues aromatize testosterone into estrogen?

Answer 17

certain neurons in the brain

Question 18

what is the primary version of inhibin produced by the sertoli cells in response to FSH?

Answer 18

Inhibin B

Question 19

when inhibin Beta units recombine, they produce ___ which ____ FSH secretion

Answer 19

activin, stimulates

Question 20

activin resides in the ___, where it has a ____ role to ___

Answer 20

FSH producing cells of the pituitary gland, paracrine, enhance the production of FSH

Question 21

in the fetus, testosterone is responsible for the development of:

Answer 21

epididymis
vas deferens
seminal vesicles

Question 22

in the fetus, DHT is responsible for the development of:

Answer 22

penis, penile urethra, scrotum, prostate

Question 23

in puberty, testosterone is responsible for the development of:

Answer 23

penis
seminal vesicles
musculature
skeleton
larynx

Question 24

in puberty, DHT is responsible for the development of:

Answer 24

scrotum prostate sexual hair sebaceous glands

Question 25

around the ___ month of fetal life, there is a temporary activation of the HPG axis and an increase in ___ secretion. Together, these increase ___ levels

Answer 25

third, hCG, testosterone

Question 26

what does fetal testosterone do?

Answer 26

- acts on the fetal hypothalamus to ensure that the system is only based on negative feedback - plays a role in the gender preference and identification of the individual

Question 27

what explains the activation of the HPG axis at birth?

Answer 27

elevations of excitatory neuronal inputs through glutamate neurons

Question 28

what is the purpose of the rise in testosterone at birth?

Answer 28

descent of the testes

Question 29

Kallman's syndrome

Answer 29

due to a failure of GnRH neurons to migrate to the hypothalamus in fetal development, wind up with hypogonadotropic hypogonadism

Question 30

how do you treat Kallman's syndrome?

Answer 30

give the patient testosterone

Question 31

precocious puberty

Answer 31

excess GnRH comes out of the hypothalamus prematurely

Question 32

how is precocious puberty treated?

Answer 32

give a GnRH superagonist analog to desensitize the pituitary

Question 33

androgen insensitivity syndrome

Answer 33

XY genotype, female appearance, undescended testes have to be removed, no female reproductive structures

Question 34

why do people with androgen insensitivity syndrome not have female reproductive structures?

Answer 34

Y chromosome has SRY gene, manufactures Mullerian inhibitory hormone

Question 35

how is estrogen made in someone with androgen insensitivity syndrome?

Answer 35

testosterone is still produced by the testes, the testosterone is converted to estrogen by the fat tissue