Reproductive Pharmacology Flashcards
What are the sources of gonadotropins? Which two sources are the most frequently used in theriogenology?
Pituitary gland: FSH and LH
Preg mares: ECG (FSH activity)
HCG: pregnant women (LH activity)
Theriogenology: hCGH and ECG
Which of these drugs has the longest plasma half-life? Why?
ECG; it has more CHOs and the glycoproteins resist breakdown
Discuss the positive feedback exerted by estrogens on the hypothalamus - pituitary - ovary axis:
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
What are the actions of FSH?
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
What are the actions of LH?
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
What are the clinical uses of FSH and LH?
Immunolgocal castration in pigs
Treat ACD in ferrets
Sterilization in wild horses
What are the clinical uses for LH and HCG?
Ovulation control, can be used to treat chronic infertility in females
What are the clinical uses of FSH and eCG?
Breed control = stimulate follicular development to cause estrus
Induction and superovulation
What is a consideration if using repeated interspecies use of eCG and hCG?
Can cause anaphylaxis
What are the actions of GnRH?
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
What are the clinical uses of GnRH receptor agonists?
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
What is the adrenocorticol disease of ferrets? What causes this? What is the mechanism of action by which leuprolide overcomes ACD?
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
What are the preparations that can be used to treat follicular cysts?
Gonadorelin analog of GnRH; given to cows to induce LH release for the treatment of follicular cysts and induce ovulation
What is the most serious adverse effect of using ECG repeatedly in the same animal?
Anaplylactic shock
What are the actions of estrogen? What are some of the clinical uses?
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
What are the actions of progesterone?
Increase glandular growth after estrogen priming. Prolongs the luteal phase of estrous.
What are some actions of androgens? What are some clinical uses?
Increase libido, spermatogenesis, growth of accessory glands.
Uses: treat impotence and infertility
What would you use to treat urinary incontinence in castrated males?
Androgen
What is an anti-steroid preparation and whtt is the use of this?
Zeranol: this is the only non-steroidal estrogen that is available in the US for beef cows as an ear implant
What is EPO, where is it produced, and what hormone prompts its secretion?
NAturally occurring hormone that is produced by the kidney that promotes erythropoiesis.
Stimulated by testosterone release
What is the problem with the use of hEPO in dogs and cats?
May induce antibodies, which would render further treatments useless
What % of circulating estrogen and androgens are bound by plasma proteins?
90%
Which globulin binds estrogen and androgens with high affinity?
SSBG binds with high affinity but low capacity
Albumin binds with low affinity but high capacity
Which sex steroids should not be administered orally?
Any natural occuring ones; subject to the first pass effect
EXCEPT: Estriol; given in high enough doses it negates this
Define ecbolic and oxytocic:
inducing contractions of the uterus
Define galactogogue:
Milk induction aka let down of milk
What is the difference between galatogogue and galactopoietic?
Galatogogue: milk let down
Galactopoietic: Promotes the production of milk
What is the action of oxytocin? Prolactin?
Oxytocin: galatogogue and uterine contractions
Prolactin: Galactopoietic (increases production of milk)
What are the 5 indications for the use of oxytocics?
Induce labor at term Treat uterine inertia Control postpartum hemorrhage and atony Induce abortions (esp after 1st trimester) Expel uterine contents
What are bromocriptine and cabergoline classified as?
Dopaminergic agonsts; inhibit prolactin and ACTH secretion
What are uses of bromocriptine and cabergoline in canine theriology?
Used to terminate pregnancies or treat psuedopregnancies
Why is cabergoline preferred over bromocriptine?
Cabergoline does not cross the BBB as much as bromocriptine
What drug would be used to treat hypo/agalactia in mares? What is it’s mechanism of action?
Domperidone
Blocks dopamine receptors, which increases prolactin secretions, which promotes the production of milk
What is the current concept regarding the role of the fetus in initiation of parturition, particularly in ruminants?
Surge of fetal cortisol and ACTH leads to luteolysis of CL, which is necessary for partruition to occur
What must be destroyed in the cow for Oxytocin to have any effect?
CL
What are the effects of estrogens and progesterone on the action of oxytocin?
Estrogen: enhances oxytocin effects; large and slow contractions
Progesterone: decreases oxytocin effects; small and rapid contractions
Which species can oxytocin alone cause partruition?
Horses and humans
What effects do ergot alkaloids have on the uterus?
Prolongs contraction of the uterine smooth muscle along with blood vessels
What can ergot alkaloids be used to treat? Which one is most commonly used?
USed to treat postpartum hemorrhage and help with uterine involution
Ergonovine = rapid onset
What is dinoprost tromethamine? What are two effects?
PGF2alpha analog that is a potent vasoconstrictor
Results in luteolysis of the CL
Strong oxytocin effect
What is the common name for dinoprost tromethamine?
Lutalyse
Lutalyse labor induction in cows and sows is due to what? What does it do in mares?
Have a CL, so it is used to induce luteolysis
Do not have a CL, so it is used for its oxytocic effects
What are some other uses for Lutalyse?
Treat pyometra and expel mummified fetuses, ovarian cysts
Synchronize estrus in cows
Can Dinoprost and clorprostenol be used in sows/gilts to synchronize estrus? Why?
NO; PGF2alpha yields inconsistent luteolysis during the luteal phase
What should you use to synchronize sows?
Progestins like altrenogest
What are some adverse effects of PGF2alpha
Placental retention
Dystocia in mares
Acute systemic toxicity like colic, tachycardia, tachypnea
Handling cautions for people who are pregnant or have asthma
What is the mechanism by which dexmethasone induces partruition?
Long acting glucocorticoid; mimics the action of fe`tal ACTH and cortisol surge resulting in luteolysis and partruition
