108 Questions
What is the primary hormone produced by the theca cells in the female reproductive system?
Androgen
What type of peptides are gonadotrophins?
Heterodimeric peptides
What is the role of LH in the ovaries?
It acts on the theca cells, causing them to produce androgens
Where is Kisspeptin expressed in the hypothalamus?
The arcuate nucleus and AVPV regions
What is the length of the active peptide in GnRH?
10 aa
What is the role of GnRH in regulating reproductive function?
It stimulates the release of both LH and FSH
What is Kisspeptin?
A biologically inactive intermediate prepropeptide
What is the mechanism of action of GnRH analogues?
They block the activity of the natural hormone GnRH in the body
GnRH analogues mimic or block the activity of the natural hormone GnRH in the __________.
body
What is the function of GnRH in the body?
It activates a signaling pathway leading to the synthesis and secretion of gonadotropins
Gonadotrophins consist of a common a-subunit and a hormone-specific beta subunit, which are ____________.
heterodimeric peptides
What is the primary function of Leydig cells in the testes?
To control spermatogenesis
How often is GnRH secreted?
Every 30-120 minutes
What clinical purposes can GnRH analogues be used for?
For a variety of clinical purposes
What is the role of FSH in the testes?
To establish a Sertoli cell population
What is the function of GAP in GnRH?
Maybe prolactin secretion
What hormone triggers the expression of the enzyme aromatase in granulosa cells?
FSH
What is the function of the alpha subunits in gonadotrophins?
Limit hormone concentration
What is the characteristic motif of Kisspeptin peptides?
Arh-Phe-NH2
What is the function of Kisspeptin neurons?
To stimulate the synthesis and release of GnRH
Gonadotrophins have N-linked carbohydrate side chains (O-linked in hCG), which may vary through the menstrual cycle or ____________.
pregnancy
How do GnRH analogues work as agonists?
They downregulate the GnRH pituitary response
What is the role of FSH in the testes?
It is necessary for the establishment of a normal population of Sertoli cells
GnRH analogues can be used for a variety of __________ purposes.
clinical
Free subunits of gonadotrophins have no ____________.
biological action
In women, what conditions can GnRH analogues be used to treat?
Endometriosis and uterine fibroids
What is the relationship between intra-testicular testosterone levels and plasma levels?
Intra-testicular levels are 100x higher than plasma levels
Which cells in the testes are responsible for the production of testosterone?
Leydig cells
What is the function of the signal peptide in GnRH?
Coordinates GnRH release from the cell
In women, GnRH analogues can stimulate __________ for fertility treatments.
ovulation
What are the gonads in males and females?
Ovaries in females and testes in males
What is the effect of a slower frequency of GnRH pulses?
It favors the release of FSH
What type of carbohydrate side chains do gonadotrophins have?
Both A and B
Which receptor is fully activated by Kisspeptin peptides?
KISS1 receptor
Which hormone is primarily responsible for the maintenance of pregnancy?
Progesterone
What is the benefit of using GnRH agonists in the treatment of hormone-dependent cancers?
They downregulate the GnRH pituitary response
What is the effect of a faster frequency of GnRH pulses?
It favors the release of LH
What is the role of estrogen in the menstrual cycle?
It triggers an LH surge, which leads to ovulation
What is the name of the peptide that is 56 aa in length in GnRH?
GAP
How do GnRH antagonists work?
They bind to the GnRH receptor and block it from activation
In men, what condition can GnRH analogues be used to treat?
Prostate cancer
GnRH analogues can treat conditions like endometriosis, uterine fibroids, and certain types of __________ cancer in women.
breast
Where does the conversion of androgens to estrogens occur in the female reproductive system?
Granulosa cells
The alpha subunits of gonadotrophins are synthesised in excess, with beta subunit production limiting the hormone ____________.
concentration
What is the role of the hypothalamus in the secretion of gonadotrophins?
Pulsatile GnRH release
Which cells in the testes contain FSH receptors?
Sertoli cells
What is the role of endopeptidases in GnRH?
Cleave the active 10 amino acid peptide from GAP
What is the purpose of using GnRH antagonists in infertility treatment?
To rapidly suppress the HPGA activity
Which enzyme converts androgens to estrogen?
Aromatase
What is the process called when the mature follicle releases the oocyte?
Ovulation
What is the function of aromatase in the testes?
To convert androgens to oestrogen
What is the benefit of using GnRH analogues during chemotherapy?
They can protect the gonads from damage
In men, GnRH analogues can treat __________ cancer by reducing testosterone production.
prostate
The secretion of gonadotrophins is pulsatile due to the pulsatile GnRH release from the hypothalamus, however pulsatile secretion of the gonadotrophins isn’t necessary for their ____________.
biological function
What happens when GnRH is continuously released?
It inhibits the release of LH and FSH
Which of the following is true about free subunits of gonadotrophins?
They have no biological action
The chains of N-linked carbohydrates side chains in gonadotrophins may vary through the menstrual cycle or ____________.
pregnancy
GnRH analogues can protect the __________ from damage during chemotherapy.
gonads
What hormone is produced by the pituitary gland and stimulates the theca cells to produce androgens?
LH
Which cells in the testes contain LH receptors?
Leydig cells
What is the role of FSH in the ovaries?
It acts on the granulosa cells, promoting follicular growth and maturation
Which organelle coordinates GnRH release from the cell?
Golgi apparatus
How do the carbohydrate side chains of gonadotrophins vary?
They vary through the menstrual cycle or pregnancy
Can GnRH analogues be used to treat all types of breast cancer?
No
Which gland responds more effectively to a slower frequency of GnRH pulses for the release of FSH?
Pituitary gland
What is the HPGA?
Hypothalamic-pituitary-gonadal axis
What is the relationship between androgens and Sertoli cell function?
Androgens cross over to and stimulate Sertoli cell function
What structure is formed from the remaining follicular cells after ovulation?
Corpus luteum
What is the structure of gonadotrophins?
Heterodimeric peptides with a common alpha subunit and a hormone-specific beta subunit
How is synthetic GnRH different from natural GnRH?
It has a different structure
The hormone-specific beta subunit of gonadotrophins is responsible for the hormone's ____________.
specificity
What is the source of GnRH secretion?
Hypothalamus
What is the function of GnRH in the body?
Stimulate ovulation
Which hormone is necessary for the maintenance of male sex characteristics?
Testosterone
This can help preserve fertility and hormone production in cancer patients undergoing __________.
treatment
How do GnRH analogues stimulate ovulation in women?
By mimicking the natural hormone GnRH
What is the role of testosterone in prostate cancer?
It can stimulate the growth of prostate cancer cells
GnRH analogues can be used to treat __________ in women.
endometriosis
The alpha subunits of gonadotrophins are synthesised in ____________.
excess
What is the effect of pulsatile secretion of GnRH on reproductive function?
It regulates reproductive function in both males and females
What is the function of progestogens in the testes?
To produce cholesterol
Which hormone is produced by the corpus luteum after ovulation?
Progesterone
What is the name of the site where endopeptidases cleave the active peptide from GAP?
P site
What is the necessary condition for the biological function of gonadotrophins?
Pulsatile secretion
Which cells in the testes are responsible for controlling spermatogenesis?
Sertoli cells
What are the gonadotropins synthesized and secreted by the pituitary gland in response to GnRH?
LH and FSH
What is the role of androgens in the ovaries?
They act on the theca cells, causing them to produce androgens
What is the length of the GAP peptide in GnRH?
56 aa
What is the role of LH and FSH in reproductive function?
They stimulate the release of testosterone in males and estrogen in females
How does GnRH activate a signaling pathway?
By binding to the GnRH receptor
In men, GnRH analogues can also be used to treat __________.
infertility
The secretion of gonadotrophins is ____________ due to the pulsatile GnRH release from the hypothalamus.
pulsatile
Which of the following is true about the beta subunit in gonadotrophins?
It is hormone-specific
What is the role of androgens in sperm production?
To initiate and maintain sperm production
Can GnRH analogues be used to treat uterine cancer?
No
What hormone do granulosa cells have receptors for?
FSH
Which hormone ultimately triggers ovulation?
LH
What is the difference between the carbohydrate side chains of gonadotrophins and hCG?
Gonadotrophins have N-linked carbohydrate side chains while hCG has O-linked carbohydrate side chains
Pulsatile secretion of gonadotrophins isn’t necessary for their ____________.
biological function
By reducing testosterone production, GnRH analogues can also be used to treat __________ in men.
hirsutism
What happens to GnRH after it binds to the GnRH receptor?
It dissociates from the receptor and waits for the next pulse
Can GnRH analogues be used to treat all types of endometriosis?
No
How does the frequency of GnRH pulses affect the release of LH and FSH?
A faster frequency favors the release of LH
What is the active peptide in GnRH?
10 aa peptide
What is the primary function of the corpus luteum?
Produce progesterone
Which hormone is responsible for establishing a quantitatively normal Sertoli cell population?
FSH
What hormone is responsible for the degeneration of the corpus luteum if fertilization does not occur?
Progesterone
What is the process called when fertilization and implantation of a fertilized egg occur?
Implantation
Study Notes
- Hypothalamic Kisspeptin regulates the HPG axis and sexual maturation.
- Kisspeptin is a protein encoded by the Kiss1 gene.
- It is expressed in the arcuate nucleus and AVPV regions of the hypothalamus.
- These regions control GnRH neurons, which release LH and FSH from the pituitary gland.
- Kisspeptin neurons stimulate the synthesis and release of GnRH.
- GnRH travels to the pituitary gland and stimulates the release of LH and FSH.
- LH and FSH stimulate the gonads to produce and release sex hormones.
- In females, the gonads are ovaries.
- In males, the gonads are testes.
- Sex hormones include estrogen and testosterone.
Test your knowledge on the role of Hypothalamic Kisspeptin in regulating the HPG axis and sexual maturation. Learn about the Kiss1 gene, the regions of the hypothalamus that control GnRH neurons, and how Kisspeptin stimulates the synthesis and release of GnRH. Explore the effects of LH and FSH on the gonads, and the production and release of sex hormones such as estrogen and testosterone. This quiz is perfect for anyone interested in endocrinology and
Make Your Own Quizzes and Flashcards
Convert your notes into interactive study material.
Get started for free
