Endocrine Infertility Flashcards
What stimulates LH and FSH release
GnRH
Where is LH and FSH released from
Pituitary
What does LH release stimulate in males and where
LH stimulates testosterone production in the testes (leydig cells)
3 phases of the female mentrual cycle?
Follicular phase -> ovulation -> luteal phase
What does LH stimulate in females and where (2)
Oestradiol and progesterone production in the ovaries
What does FSH stimulate in females and where (2)
FSH stimulates follicular development and inhibin production
What does inhibin do
Inhibit FSH
What does FSH release stimulate in males and where
FSH stimulates sertoli cells in seminiferous tubules -‐-‐> sperm and inhibin A and
B
How is GnRH released (time)
Pulsatile
What cells produce testosterone in males testes
leydig cells
what is testosterone responsible for (2)
secondary sexual characteristics and aids spermatogenesis
What cells produce sperm and and inhibin
Sertoli cells in seminiferous tubules
What does testosterone inhibit
has negative feedback on the hypothalamus and the pituitary (GnRH and FSH/LH)
What does inihibin inhibit in males
FSH
What day is the Graffian follicle developed
10
Oestrogens initial effect on hormone secretion in females?
Oestrogen initially has negatively inhibits LH and FSH secretion
When does oestrogens effect on LH and FSH change in females
In the luteal phase
What does oestrogen do in the luteal phase (2)
It increases GnRH release and increases LH sensitivity to GnRH
This leads to a mid-‐cycle LH surge
What does the LH surge do
This triggers ovulation from the leading follicle
What is infertility defined as
Definition: inability to conceive after 1 year of regular unprotected sex
1/6 couples can be affected
What is primary gonadal failure
Testes or ovaries not working
What are the levels of testosterone/oestradiol in primary gonadal failure
- Low
Levels of GnRH, LH, FSH, testosterone/oestradiol in primary gonadal failure? Why
- Low negative feedback
- High GnRH
- High LH/FSH
What is secondary gonadal failure
Hypo/pituitary disease
Levels of GnRH, LH, FSH, testosterone/oestradiol in secondary gonadal failure? Why
- Low LH/FSH
- Low testosterone/oestradiol
ENDOGENOUS SITES OF ANDROGEN PRODUCTION: (5)
Interstitial Leydig cells of the testes Adrenal cortex (males and females) Ovaries Placenta Tumours
MAIN ACTIONS OF TESTOSTERONE: (40
- Development of male genital tract
- Maintains fetility in adulthood
- Control of secondary sexual characteristics
- Anabolic effects (muscle/bone)
What converts testosterone to dihydrotestosterone
5alpha-reductase