two cell theory part 1

Question 1

what do leydig cells produce

Answer 1

testosterone in response to LH stimulation

Question 2

what are sertoli cells stimulated by

Answer 2

stimulated by FSH and testosterone and leading to sperm production

Question 3

how does leydig cells help cAMP cascade

Answer 3

-respond to LH
-LH starts cAMP cascade

Question 4

a compound that blocks adenylate cyclase will do what to testosterone production

Answer 4

decrease

Question 5

why is the cAMP cascade important

Answer 5

-leads to StAR production (steroidogenic acute regulatory protein) causing cholesterol to move from outer to inner mitochondrial membrane

Question 6

why do we need StAR production

Answer 6

produces androgens (testosterone)

Question 7

what are the cell products that sertoli cells produce that lead to proper sperm production

Answer 7

CREB

Question 8

what does the activation of CREB do

Answer 8

activate transcription from the promoters of numerous genes

Question 9

researchers injected mutated CREB into the seminiferous tubules of rats.

1. what happened to the amt of spermatocytes?
2. what happens to spermatids?
3. what does CREB do to sperm maturation
4. what impact does this have on sperm production

Answer 9

1. relatively the same
2. decrease
3. help go from spermatocytes to spermatids
4. decrease

Question 10

researchers cultured mouse testes with or without SCF.

1. what happens to rates of apoptosis in cells cultured without SCF?
2. which cells seem to be affected

Answer 10

1. increase in cell death
2. spermatogonium, spermatocytes, spermatids

-SCF (stem cell factor) important for survival of spermatogonia, spermatocytes, and spermatids

Question 11

why is GDNF released by sertoli cells necessary

Answer 11

required for survival and proliferation of spermatogonia

Question 12

what are the effects of abnormally elevated GDNF

Answer 12

-increases division of spermatogonia
-prevents differentiation
-increased apoptosis
-increased GDNF can lead to tumors
-cells are not able to differentiate into spermatids with high levels of GDNF

Question 13

what are major regulators of proliferation and differentiation

Answer 13

GDNF and SCF

Question 14

what would happen if sertoli cells did not secrete ABP

Answer 14

inadequate levels of testosterone would remain in the seminiferous tubule

Question 15

what is the function of ABP

Answer 15

-ABP helps keep testosterone in the lumen of the seminiferous tubule, without high testosterone, sperm production drops

Question 16

are there receptors for testosterone in spermatocytes

Answer 16

no

Question 17

what does testosterone do to sperm cells

Answer 17

cleaves sperm cells off sertoli cells

Question 18

what would happen to sperm production if we had elevated levels of inhibin released by our sertoli cells

Answer 18

-decrease in sperm production bc FSH stimulates spermatogenesis in sertoli cells
-GnRH normal
-LH normal –> testosterone normal
-FSH low –> decrease sperm production
-FSH makes KREB, GDNF, SCP