Regulation of gonadal function

Question 1

Describe the role of the hypothalamus in the regulation of gonadal function.

Answer 1

The hypothalamus secretes GnRH in a pulsatile manner in response to stimuli from the cerebral cortex and limbic system, which stimulates the secretion of LH and FSH by the pituitary gland.

Question 2

What is the effect of faster pulse frequencies of GnRH secretion?

Answer 2

Faster pulse frequencies of GnRH secretion favor LH secretion.

Question 3

What is the effect of slower pulse frequencies of GnRH secretion?

Answer 3

Slower pulse frequencies of GnRH secretion favor FSH secretion.

Question 4

How can long-acting GnRH analogues be used in the treatment of prostate cancer and endometriosis?

Answer 4

Long-acting GnRH analogues can be used to suppress sex steroid levels.

Question 5

What is the role of LH in gonadal function?

Answer 5

LH drives interstitial cell synthesis and secretion of testosterone in both sexes and triggers ovulation in females.

Question 6

What is the role of FSH in male gonadal function?

Answer 6

FSH in males drives Sertoli cell-mediated sperm maturation and production of seminiferous tubule fluid.

Question 7

What is the role of FSH in female gonadal function?

Answer 7

FSH in females drives granulosa cell-mediated aromatization of androgens to estradiol.

Question 8

What hormones are produced by Leydig cells in the gonads?

Answer 8

Leydig cells produce testosterone, androstenedione, DHEA, and dihydrotestosterone (DHT).

Question 9

Describe the circadian rhythm of testosterone production in males.

Answer 9

In males, testosterone has a circadian rhythm, with maximum secretion at around 8 a.m. and minimum at around 9 p.m.

Question 10

When does testosterone production peak in females?

Answer 10

Testosterone production in females peaks at ovulation.

Question 11

How is estradiol produced in males?

Answer 11

In males, estradiol is mainly produced through peripheral conversion from androgens.

Question 12

How is estradiol produced in females?

Answer 12

In females, estradiol rises with follicle maturation under FSH drive of granulosa cells. It is also produced by the placenta, adrenal, and corpus luteum.

Question 13

Where is progesterone secreted from?

Answer 13

Progesterone is secreted from the corpus luteum, which is derived from luteinized granulosa cells in the remnants of the follicle following ovulation. It is also secreted from the placenta.

Question 14

What is the role of LH in gametogenesis?

Answer 14

LH ensures high intragonadal concentrations of testosterone, which is vital for gametogenesis.

Question 15

What is the role of FSH in gametogenesis?

Answer 15

FSH, through its action on Sertoli cells in males and granulosa cells in females, is vital for sperm and follicle growth, respectively.

Question 16

How long does the process of spermatogenesis take in males?

Answer 16

The whole process of spermatogenesis takes approximately 74 days, followed by another 12-21 days for sperm transport through the epididymis.

Question 17

How long does it take for a primordial follicle to develop into a preantral follicle in females?

Answer 17

From primordial follicle to 1° follicle, it takes about 180 days, and another 60 days to form a preantral follicle.

Question 18

What drives the development of a dominant follicle in females?

Answer 18

A dominant follicle is driven by FSH over 2-3 weeks and ovulates following the mid-cycle LH surge.

Question 19

How long can it take for events affecting spermatogenesis to become apparent?

Answer 19

Events that may affect spermatogenesis may not be apparent for up to 3 months.

Question 20

How long can it take for successful induction of spermatogenesis treatment?

Answer 20

Successful induction of spermatogenesis treatment may take up to 2 years.

Question 21

What are some of the neurotransmitters that stimulate GnRH secretion?

Answer 21

Neurotransmitters such as leptin, kisspeptin, endorphins, catecholamines, and dopamine stimulate GnRH secretion.

Question 22

How does continuous administration of GnRH affect the reproductive axis?

Answer 22

Continuous administration of GnRH leads to downregulation of the reproductive axis.

Question 23

What are some examples of long-acting GnRH analogues?

Answer 23

Some examples of long-acting GnRH analogues are goserelin, triptorelin, and leuprorelin.

Question 24

How does continuous administration of GnRH affect the reproductive axis?

Answer 24

Continuous administration of GnRH leads to downregulation of the reproductive axis.

Question 25

What are some examples of long-acting GnRH analogues?

Answer 25

Some examples of long-acting GnRH analogues are goserelin, triptorelin, and leuprorelin.

Question 26

What is the role of FSH in the male reproductive system?

Answer 26

FSH in males drives Sertoli cell-mediated sperm maturation and production of seminiferous tubule fluid.

Question 27

What is the role of FSH in the female reproductive system?

Answer 27

FSH in females drives granulosa cell-mediated aromatization of androgens to estradiol.