Reproductive Pharmacology

Question 1

What are the sources of gonadotropins? Which two sources are the most frequently used in theriogenology?

Answer 1

Pituitary gland: FSH and LH
Preg mares: ECG (FSH activity)
HCG: pregnant women (LH activity)

Theriogenology: hCGH and ECG

Question 2

Which of these drugs has the longest plasma half-life? Why?

Answer 2

ECG; it has more CHOs and the glycoproteins resist breakdown

Question 3

Discuss the positive feedback exerted by estrogens on the hypothalamus - pituitary - ovary axis:

Answer 3

Hypothalamus get estrogen
Hypothalamus releases GnRH
GnRH goes to pit gland and stimulates FSH release
FSH goes to the ovary and stimulates conversion of Estrogen
This continues until the dominate follicle ovulates

Question 4

What are the actions of FSH?

Answer 4

Females: stimulates development of follicles.

Males: Increases the diameter of seminiferous tubules and increases the development of spermatozoa from spermatids due to increased androgen binding

Question 5

What are the actions of LH?

Answer 5

Female: ovulation and leutilization: increase in P4 and estrogen

Male: proliferation of Leydig cells = increased testosterone
Females in estrus can release pheromones to stimulate LH release from males and increase testosterone

Question 6

What are the clinical uses of FSH and LH?

Answer 6

Immunolgocal castration in pigs

Treat ACD in ferrets

Sterilization in wild horses

Question 7

What are the clinical uses for LH and HCG?

Answer 7

Ovulation control, can be used to treat chronic infertility in females

Question 8

What are the clinical uses of FSH and eCG?

Answer 8

Breed control = stimulate follicular development to cause estrus
Induction and superovulation

Question 9

What is a consideration if using repeated interspecies use of eCG and hCG?

Answer 9

Can cause anaphylaxis

Question 10

What are the actions of GnRH?

Answer 10

E, LH, and FSH stimulate GnRH release, which then stimulates more LH and FSH release

Can induce ovulation and increase conception in female and increase libido in males

Question 11

What are the clinical uses of GnRH receptor agonists?

Answer 11

Leuprolide acetate is used to treat adrenocorticol disease in ferrets neutered too early

These animals suffer from an overstimulation of FSH and LH

This down regulates GnRH receptors, which decreases FsH and LH

Question 12

What is the adrenocorticol disease of ferrets? What causes this? What is the mechanism of action by which leuprolide overcomes ACD?

Answer 12

Early neutering causes the ferrets to have excess sex steroids

Leuprolide is a GnRH-R agonist that will decrease GnRH-R

Down regulates sex steroid release

Question 13

What are the preparations that can be used to treat follicular cysts?

Answer 13

Gonadorelin analog of GnRH; given to cows to induce LH release for the treatment of follicular cysts and induce ovulation

Question 14

What is the most serious adverse effect of using ECG repeatedly in the same animal?

Answer 14

Anaplylactic shock

Question 15

What are the actions of estrogen? What are some of the clinical uses?

Answer 15

Stimulate and maintain the repro tract and cause hyperemia, hypertrophy, and edema in the tract during estrus.

Cervical dilation, growth of mammary gland, and increase sexual receptivity

Uses: Estrus induction in anestrus bitches, mismatching therapy

Question 16

What are the actions of progesterone?

Answer 16

Increase glandular growth after estrogen priming. Prolongs the luteal phase of estrous.

Question 17

What are some actions of androgens? What are some clinical uses?

Answer 17

Increase libido, spermatogenesis, growth of accessory glands.

Uses: treat impotence and infertility

Question 18

What would you use to treat urinary incontinence in castrated males?

Answer 18

Androgen

Question 19

What is an anti-steroid preparation and whtt is the use of this?

Answer 19

Zeranol: this is the only non-steroidal estrogen that is available in the US for beef cows as an ear implant

Question 20

What is EPO, where is it produced, and what hormone prompts its secretion?

Answer 20

NAturally occurring hormone that is produced by the kidney that promotes erythropoiesis.
Stimulated by testosterone release

Question 21

What is the problem with the use of hEPO in dogs and cats?

Answer 21

May induce antibodies, which would render further treatments useless

Question 22

What % of circulating estrogen and androgens are bound by plasma proteins?

Answer 22

90%

Question 23

Which globulin binds estrogen and androgens with high affinity?

Answer 23

SSBG binds with high affinity but low capacity

Albumin binds with low affinity but high capacity

Question 24

Which sex steroids should not be administered orally?

Answer 24

Any natural occuring ones; subject to the first pass effect

EXCEPT: Estriol; given in high enough doses it negates this

Question 25

Define ecbolic and oxytocic:

Answer 25

inducing contractions of the uterus

Question 26

Define galactogogue:

Answer 26

Milk induction aka let down of milk

Question 27

What is the difference between galatogogue and galactopoietic?

Answer 27

Galatogogue: milk let down Galactopoietic: Promotes the production of milk

Question 28

What is the action of oxytocin? Prolactin?

Answer 28

Oxytocin: galatogogue and uterine contractions Prolactin: Galactopoietic (increases production of milk)

Question 29

What are the 5 indications for the use of oxytocics?

Answer 29

``` Induce labor at term Treat uterine inertia Control postpartum hemorrhage and atony Induce abortions (esp after 1st trimester) Expel uterine contents ```

Question 30

What are bromocriptine and cabergoline classified as?

Answer 30

Dopaminergic agonsts; inhibit prolactin and ACTH secretion

Question 31

What are uses of bromocriptine and cabergoline in canine theriology?

Answer 31

Used to terminate pregnancies or treat psuedopregnancies

Question 32

Why is cabergoline preferred over bromocriptine?

Answer 32

Cabergoline does not cross the BBB as much as bromocriptine

Question 33

What drug would be used to treat hypo/agalactia in mares? What is it's mechanism of action?

Answer 33

Domperidone Blocks dopamine receptors, which increases prolactin secretions, which promotes the production of milk

Question 34

What is the current concept regarding the role of the fetus in initiation of parturition, particularly in ruminants?

Answer 34

Surge of fetal cortisol and ACTH leads to luteolysis of CL, which is necessary for partruition to occur

Question 35

What must be destroyed in the cow for Oxytocin to have any effect?

Answer 35

CL

Question 36

What are the effects of estrogens and progesterone on the action of oxytocin?

Answer 36

Estrogen: enhances oxytocin effects; large and slow contractions Progesterone: decreases oxytocin effects; small and rapid contractions

Question 37

Which species can oxytocin alone cause partruition?

Answer 37

Horses and humans

Question 38

What effects do ergot alkaloids have on the uterus?

Answer 38

Prolongs contraction of the uterine smooth muscle along with blood vessels

Question 39

What can ergot alkaloids be used to treat? Which one is most commonly used?

Answer 39

USed to treat postpartum hemorrhage and help with uterine involution Ergonovine = rapid onset

Question 40

What is dinoprost tromethamine? What are two effects?

Answer 40

PGF2alpha analog that is a potent vasoconstrictor Results in luteolysis of the CL Strong oxytocin effect

Question 41

What is the common name for dinoprost tromethamine?

Answer 41

Lutalyse

Question 42

Lutalyse labor induction in cows and sows is due to what? What does it do in mares?

Answer 42

Have a CL, so it is used to induce luteolysis Do not have a CL, so it is used for its oxytocic effects

Question 43

What are some other uses for Lutalyse?

Answer 43

Treat pyometra and expel mummified fetuses, ovarian cysts | Synchronize estrus in cows

Question 44

Can Dinoprost and clorprostenol be used in sows/gilts to synchronize estrus? Why?

Answer 44

NO; PGF2alpha yields inconsistent luteolysis during the luteal phase

Question 45

What should you use to synchronize sows?

Answer 45

Progestins like altrenogest

Question 46

What are some adverse effects of PGF2alpha

Answer 46

Placental retention Dystocia in mares Acute systemic toxicity like colic, tachycardia, tachypnea Handling cautions for people who are pregnant or have asthma

Question 47

What is the mechanism by which dexmethasone induces partruition?

Answer 47

Long acting glucocorticoid; mimics the action of fe`tal ACTH and cortisol surge resulting in luteolysis and partruition