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Y2 URO > 3. approach to manipulating reproduction ws > Flashcards

3. approach to manipulating reproduction ws Flashcards

1
Q

where does GnRH come from

A

hypothalamus

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2
Q

how is GnRH produced/controlled

A
  • Pulsatile secretion controlled by tonic centre
  • Suppressed by progesterone
  • Low oestradiol suppresses GnRH release, while high oestradiol
  • stimulates a GnRH surge
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3
Q

what is the taget tissue of GnRH in the female

A

anterior pituitary gland

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4
Q

what is the source of FSH

A

anterior pituitary

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5
Q

how is FSH produced/contolled

A
  • GnRH (stimulatory)
  • Inhibin / oestradiol (inhibitory)
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6
Q

what is the target tissue of FSH in the female

A

follicle (granulosa cells)

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7
Q

where does LH come from

A

anterior pit

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8
Q

how is LH produced/controlled

A
  • GnRH (stimulatory)
  • pulsatile release
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9
Q

what is the target tissue of LH in the female

A
  • follicle (theca cells and granulosa in the dominant follicle)
  • small luteal cells
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10
Q

where does oestradiol come from

A

antral follicles

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11
Q

how is oestradiol produced/controlled

A
  • Co-ordinated action of LH on theca to produce androgens and FSH on granulosa to produce oestradiol via aromatase
  • As follicle grows E2 increases
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12
Q

what are the target tissue of oestradiol in the female

A
  • uterus
  • hypothalamus
  • anteriro pit gland
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13
Q

why might we want to manipulate reproduction and/or use reproductive hormones?

A
  • synchronise the herd
  • helps for ART and to time so all give birth at similar times
  • induce parturition
  • abortion
  • stimulate ovulation
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14
Q

where does progesterone come from

A

CL

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15
Q

how is progesterone produced/controlled

A

LH acting on luteal cells stimulates progesterone production

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16
Q

what is the target tissue of progesterone in the female

A
  • uterus
  • hypothalamus
  • mammary gland
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17
Q

where does oxytocin come from

A
  • CL
  • posterior pit
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18
Q

how is oxytocin produced/controlled

A

pulsatile secretion of pgf2a

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19
Q

what is the target tissue of oxytocin in the female

A
  • uterus
  • mammary gland
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20
Q

where does pgf2a come from

A

epithelial cells in endometrium

21
Q

how is pgf2a produced/controlled

A

oxytocin acting on endometrial oxytocin receptors stimulates pgf2a

22
Q

what is the target tissue of pgf2a in the female

23
Q

in which stage of the cycle is this cow. day 30 post mating, no uterine enlargement, no fetal fluids

A

may be pregnant but probably not, should be able to feel a bit of uterine enlargment (def by day 42), should see fetal fluids by day 28

phase: luteal –> has CL
day 9 of cycle (30-21) ish

24
Q

what phase of the cycle is this cow in? she is presented as oestrus has not been observed 60 days after calving. uterus has involuted and no sigsn of endometritis

A
  • we expect her to have come into oestrus. should have started cycling around 25 days post calving
  • left ovary: small, lots of small follicles
  • right ovary: large follicle (maybe too large)

= follicular stage. NO CL
she should be around oestrus now - why not. what can we do to get her back into calf

25
what are the primary actions of GnRH in the female
stimulates FSH and LH release
26
what are the primary actions of FSH in the female
- stimulate E2 - stimulates recruitment of small antral follicles
27
what are the primary actions of LH in the female
- stimulates dominance and growth of large follicles - stimulates E2 and ovulation - luteal P4 production
28
what are some potential pharmacological effects if in follicular phase there is a dominant follicle and no active CL and GnRH is given
- LH surge - ovulation wont induce oestrus per say, she might happen to be in oestrus but its primary action is inducing oestrus
29
what are some potential pharmacological effects if in follicular phase there is a dominant follicle and no active CL and FSH is given
- stimulate to grow and produce oestradiol - but not going to have any dramatic effect - can trigger superovulation but not in this case because we have a dominant follicle (needs to have been given in the luteal phase repeatedly when follicle wave is growing)
30
what are some potential pharmacological effects if in follicular phase there is a dominant follicle and no active CL and LH is given
Ovulation of DF;  Luteinisation of follicular cells  At low doses increase E2.  At high doses switch E2 production off
31
what are the potential pharmacological effects if an animal is in the luteal phase (dominant CL and follicles at different stages that can include DF) and GnRH is given
- cause LH surge - stimulate more progesterone production from CL - ovulate dominant follicle (even though progesterone is supressing ovulation. prog inhibits ovulation through negative feedback on GnRH but we have bypassed and given LH) - makes accessory CL
32
what are the potential pharmacological effects if an animal is in the luteal phase (dominant CL and follicles at different stages that can include DF) and FSH is given
depends on where we are in stage of luteal - can increase dominant follicles if given at end of one wave and beginning of another (must be given when we have a growing follicle, NOT when we alreayd have a dominant follicle
33
what are the potential pharmacological effects if an animal is in the luteal phase (dominant CL and follicles at different stages that can include DF) and LH is given
- stimulate more progesterone production from CL - ovulate dominant follicle (even though progesterone is supressing ovulation. prog inhibits ovulation through negative feedback on GnRH but we have bypassed and given LH) - makes accessory CL
34
what is the primary action of oestradiol in the female
- Oestrus behaviour  - GnRH release (inhibitory at low concentrations; stimulatory at high) 
35
what is the primary action of progesterone in the female
- Uterus: histotroph   - suppress oestrus  - Suppress GnRH / ovulation 
36
what is the primary action of oxytocin in the female
- pgf2a production if OXTR are present
37
what is the primary action og pgf2a in the female
regression of the CL
38
is oestradiol is administered in the follicular phase what happens
- oestrus behaviour - GnRH/LH surge - ovulation
39
if progesterone is administered in the follicular phase what happens
- would enter luteal phase - inhibit ovulation - inhibit oestrus
40
is oxytocin is administered in the follicular phase what happens
no effect - might stimulate uterine contraction, might help luteolysis along
41
is pgf2a is administered in the follicular phase what happens
no effect - will increase regression of CL of already regressing CL
42
is oestradiol is administered in the luteal phase what happens
- could induce LH surge - but doesnt really do anything. if high does given will induce luteolysis
43
is progesterone is administered in the luteal phase what happens
suppression of gonadotrophin and hence follicular maturation might attenuate luteolysis
44
is oxytocin is administered in the luteal phase what happens
- no effect really. - stimulates pgf2a release IF receptors are there (day 15,16,17 of cycle) - might help along luteolysis. but will only shorten cycle by about a day. not used to manipulate cyclicity
45
is pgf2a is administered in the luteal phase what happens
- cause regression of CL - progesterone declines - enters follicular phase/prooestrus - come into oestrus within 3-4 days - doesnt have much effect though on growing or regressing CL
46
in ruminants and pigs, luteolysis requires hormonal communication between which structures
CL and uterine endometrium
47
how is luteolysis initiated
48
how can you induce breeding opportunity in the below scenario
she is in luteal phase want to induce luteolysis with pgf2a - AI her as soon as you notice standing oestrus (3-4 days after admin but maybe 4-5 days as says right ovary only has small follicles. need to give time to grow) - could then inject GnRH 2-3 days later to ensure ovulation happens - AI her at 2-3 days whether she is displaying signs of oestrus or not
49
how can you induce breeding opportunity in the below scenario
- she is in follicular phase as DF present - might be in or about to be in oestrus (increased uterine tone) - so AI her as will be coming into oestrus tomorrow or day after - give GnRH/LH to cause LH surge and thus ovulation

Y2 URO (106 decks)

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