hormones and reproduction Flashcards

Question

what is an example of synthetic agonist or antagonist of GnRH?

Answer 1

both shut down the ovary – sometimes this is used in IVF to stimulate and collect eggs, this stops the production of FSH and LH. If you use an agonist is down regulates itself, either way production of GnRH is stalled. The antagonist would block the receptor of LH and FSH snd this would stop production of GnRH.

Answer 2

``` is an agonist at the GnRH receptor. It can stimulate FSH and LH production. You can use this to create an artificial cycle, but long term constant levels cause: - GnRHR down-regulation - resulting insensitivity to GnRH - loss of production of FSH and LH H-Pyr-His-Trp-Ser-Tyr-D-Ser(tBu)-Leu-Arg-Pro-NHEt ```

Answer 3

leptin (fat muscles), as they age there is an increased in fat levels and this affects GnRH neurone in turn leading to production of gonadotropin

Answer 4

* Early puberty is associated with higher risks of type 2 diabetes (T2D) and cardiovascular disease in women and men. * Increasing age at menarche is associated with higher risks for osteoporosis but lower risks for breast cancer. * Higher levels of fat usually do come with an increased risk of T2D so this could just be coincidence.

Answer 5

granulosa cells - these contain full chromosomal complement

Answer 6

- ovulation stimulated by LH - FSH stimulates the growth of follicle from primary to secondary to tertiary - corpus leutum is stimulated by LH

Answer 7

corpus leutum regresses and the hormones will decline

Answer 8

We have production of oestrogen at low levels, you get slow GnRH pulses and FSH is starting to respond to this and increase but not too much and encourage promotion cohort of follicles

Answer 9

FSH production is now starting to decline this coincides with an increase of oestrogen. This is an example of oestrogen exerting negative feedback on the hypothalamic production of GnRH. As oestrogen begins to rise there is a negative feedback down regulation action, which stops increase of FSH production. As you get closer to ovulation it hits the transient phase, during which the oestrogen is acting positively feeding back to the hypolathmic and pituitary axis. This is the only time that positive feedback occurs.\this is what gives you the spike of LH just before ovulation. This only occurs when the level is at the highest. Then oestrogen levels decline and it goes back to negative feedback

Answer 10

you get negative feedback from progesterone aswell as the oestrogen. This causes a decrease in GnRH and LH. Post ovulation LH and FSH are both declining. The spike of gluttonising enzyme in the green occurs 36 hours before ovulation, as an increase in FSH stimulates ovulation. In fertility centres people either look for early rise of LH or the spike of LH, but the plot is not very resolved as the dotted line at 14 hours should be more to the right. It is at the negative feedback where you can inhibit the enzymes and stop the cyclical production of the ovaries. You can do the same in the male testes. Combined E2 and P (prostergone like compounds) inhibit GnRH. Prolonged high E2 (this isn't usually used as it is more dangerous effects) alone also has this effect.  contraceptive options.

Answer 11

Steroids binds receptors in the cell (semi circle) this complex goes to the nucleus and binds to subset of genes which has a specific sequence. And the effect of this is to recruit co-activators and this stimulates the rate of mRNA. This allows the gene to respsond in response to a steroid.

Answer 12

binds the estrogen receptor and blocks its ability to activate target genes. This doesn’t create a complex which can activate in that way. whole range of compounds that have a range of activities which postion them between a full agonist and a full antagonist so they are partial of both