Endocrinology of pregnancy

Question 1

When does maternal recognition of pregnancy occur?

Answer 1

-BEFORE luteolysis

Question 2

List the 6 placental hormones

Answer 2

1) Progesterone
2) Oestrogens
3) Chorionic gonadotrophin
4) Prolactin
5) Placental lactogen
6) Relaxin

Question 3

What is RU486?

Answer 3

A progesterone antagonist that acts as a contraceptive or induces abortion

Question 4

What is the difference in progesterone profiles in short/ long gestation periods?

Answer 4

Short= progesterone high at beginning the slowly decreases BUT stays high until right at the end when suddenly drops off
Long= can have an increase in progesterone levels as placenta takes over production

Question 5

In what species does placental take over occur?

Answer 5

Cow: 6-8 months
Ewe: 50 days
Mare: 140-210 days

Question 6

What are endometrial cups in the mare formed by?

Answer 6

Invasion from foetal trophoblast

Question 7

When do the endometrial cups appear?

Answer 7

Approx day 40

Question 8

What do the endometrial cups produce?

Answer 8

eCG

Question 9

Describe the function of accessory CL’s and how they’re produced

Answer 9

• Act to increase concentration of progesterone
• Formed due to the FSH/ LH like action of eCG which is secreted by the endometrial cups.
• Promotes production of P4 and stimulates ovulation so they form accessory CLs

Question 10

What inhibits/ stimulates prolactin?

Answer 10

Inhibited by dopamine

Stimulated by oestradiol

Question 11

In the bitch what is luteal progesterone dependant on?

Answer 11

LH and prolactin

Question 12

Describe the progesterone profile in pregnant queens

Answer 12

• Pregnant cats have a longer luteal phase than non pregnant
• Placenta capable of producing some P4 but not enough to maintain pregnancy.

Question 13

What are the key agents for pregnancy termination?

Answer 13

• PGF2a
• Corticosteroids
• Oestradiol
• Dopamine agonists
• P4 receptor antagonists

(For premature induction of parturition–> oxytocin to stimulate myometrial contractions of PGF2a)

Question 14

Why isn’t premature induct of parturition desirable in the mare?

Answer 14

Because of the cups

Question 15

At what stage of gestation does PGF2a become ineffective at terminating pregnancies in mares?

Answer 15

Day 35= this is when the cups start to become established, these secrete eCG which renders the prostaglandin ineffective

Question 16

What is Aglepristone?

Answer 16

An antiprogestin used to terminate pregnancies in dogs

Question 17

What is dexadressin?

Answer 17

A corticosteroid used to induce premature labour

It mimics fetal signals (fetal cortisol) which induced myometrial contractions.