Hypothalamic/Pituitary/Gonadal Axis Flashcards
Male and female gonadal function is controlled by hormonal feedback of what?
- hypothalamic and pituitary peptides
- gonadal steroids and peptides
What has to be achieved to reproduce?
- Differentiation into male and female
- Sexual maturation
- Production and storage of sufficient supply of eggs and sperm
- Correct number of chromosomes in eggs and sperm
- Gamete transport and meet
GnRH action
Pulsatile release is critical for normal pituitary function.
Receptors are internalised in the cell after initial binding so only one pulse occurs
GnRH analogues
Prevents the breakdown by enzymes at the pituitary and receptor internalisation therefore longer half life and loss of pulsality
What can GnRH be used for?
Reinstate missing hypothalamic functions
Always given in pulsatile fashion
What can GnRH analogues used for?
Only used to shut off pituitary
Causes of loss of pulsatility which removes LH and FSH which therefore inhibits the stimulation on gonads
Examples of when GnRH analogues are used
- Testicular cancer which is dependent on testosterone for growth
- Uterine fibroids prior to surgery (oestrogen dependent)
- Prevention of premature ovulation in IVFs
Examples of GnRH analogues
Gonadreline
Triptoreline
What type of hormones are LH, FSH and hGH?
Peptide hormones
LH and FSH are always released in pulses in normal reproductive function
TRUE or FALSE
TRUE
Gonadotropins are not day/night sensitive
TRUE or FALSE
FALSE
What type of receptors are Gonadotropin receptors?
G coupled protein membrane linked receptors
- cAMP as second messenger
What types of receptors are present in the testes?
Sertoli cells - FSH receptors to make AMH and oestrogen a
Leydig cells - FSH and LH receptors to make testosterone and oestrogen
What types of receptors are present in the ovary?
Granulosa cells - FSH receptors only to make oestrogen
LH receptors are always found on the theca cells, differentiated granulosa and corpus luteum
What does LH always stimulate?
Androgen production
