Reproductive Pharmacology Flashcards
______________ regulates overall reproduction
Hypothalamus
What 2 hormones come from the hypothalamus
Gonadotropin releasing hormone (GnRH)
Dopamine: prolactin- inhibitor hormone
They stimulate/ inhibit the release of anterior pit hormones
Anterior pituitary glands
Gonadotropins: FSH and LH (act on ovaries + negative feedback on pituitary)
Prolactin
GnRH
Targets anterior pit. to release LH and FSH
Pulsatile release
Increased and decreased GnRH
↑= secretion of LH
↓= greater FSH release
Continuous administration of GnRH
Desensitization and down regulation of GnRH receptors on pituitary gonadotropes
Medical castration
Follitropin
FSH
Superovulation in cattle
Folluttein and Chrorulon
hCG
Horses: infertility, male impotence
Cow: cystic ovaries
Pig: induce estrus
Cats: pseudopregnancy
Dog: cryptorchidism
Ovagen and Pg600 combo
In anestrus for sheep and goat: stimulates ovarian follicular growth
Pig: induces estrus
Mentropins
Mostly FSH like effect
Cattle: superovulation
Gonadorelin
Causes surge like release of FSH and LH
Ovulation induction, infertility treatment
Extralabel use of gonadorelin
GnRH stimulation test to differentiate castration from cryptorchidism
Cystic ovarian disease in bitches
Detect ovarian remains in queens after OVH
Superelorin use in mares
GnRH analog
Estrual mares to induce ovulation by ↑ LH and inducing ovulation within 48 hrs
Superelorin use in other animals
Adrenal disease in ferrets (restricted in major species)
Birds with chronic egg-laying/ behavioral
Contraceptive
Aggression in males
Gonadotropins MOA
LH and hCG act on LH receptor
FSH on FSH receptor
eCG on both receptors ^
G-protein coupled receptors ↑ cAMP levels
eCG
FSH like activity
Except in horses LH like activity
Super ovulation
Leuprolide (LH agonist)
Negative feedback: Initially ↑ FSH and LH, then inhibits them
Estrogen and androgen levels ↓ in serum
Leuprolide uses
Chronic egg laying in birds
Ovarian cysts in GPs
Legal note about GnRH products
Illegal to use products in combination with another drug for estrous synchrony unless approved combos
Prolactin
Major regulator is dopamine (agonist= inhibit)
Stimulates lactation in postpartum period
No analog
Metoclopramide
↑ prolactin: dopamine antagonist
Antiemetic in small animal, ↑ GI motility in small and large animals
Domperidone
↑ prolactin: dopamine antagonist
Stimulates ↑ in lactation through prolactin stimulation
Treatment for fescue toxicosis causing agalactia
Oxytocin in the uterus
Stimulates frequency and force of uterine contraction
Effects dependent on estrogen
Progesterone antagonizes stimulant effect of oxytocin
Oxytocin in the mammary gland
Induces contraction of smooth muscle, resulting in milk ejection
Oxytocin MOA
G-protein coupled membrane receptors
Activation lead to generation of IP3 (metabolizes Ca2+)
Depolarization-contraction of smooth muscle tissue with oxytocin contractions
Clinical uses of oxytocin
Labor induction (make sure there’s no obstruction, can cause uterine rupture)
Milk let down
Persistent endometritis (mare)
Dinoprost (PGF2a analog)
Luteolytic agent produced by the endometrium
Activates GPCR linked to IP3 Ca2+ protein kinase pathway (↓ steroidogenesis and luteolysis)
Dinoprost function
↓ progesterone via luteolysis of the CL
↓ placental progesterone production
Dinoprost clinical uses
Estrus synchronization
Abortion and parturition in dogs
Uterine contractions in cows
Mating-induced endometritis in mare
Uterine infections in bitches
Inducing parturition in sow
Dinoporost adverse reactions
↑ smooth muscle tones→ diarrhea, abdominal discomfort, bronchoconstriction, ↑ BP
Inducement of abortion leading to retained placenta
Dinoprost should not be handled by ___________
Pregnant women
can be absorbed through the skin
MOA of estrogen and progesterone
Binds to intracellular steroid hormones
Hormone-receptor complex interacts with DNA at hormone response elements (transcription factor)
Clinical use for estradiol
Neg feedback of LH and FSH
Estrus synchronization
Urinary incontinence and perianal gland adenoma in dogs
Progestins
Long lasting ovarian suppression and synchornization of estrous cycle
↑ feedback and ↓ LH and FSH output
Altrenogest (progestin)
Controls estrus cycle in mare and pig
High doses: fetal abnormalities in horses
Melengstrol Acetate (progestin)
Approved: medicated feed to suppress estrus in heifers
Not: synchronizing estrous cycle/ advancing estrus in heifers
Parturition in cattle
Glucorticoids (dexamethasone, flumethasone)
PGF2a, cloprostenol
Parturition in other animals
Farrowing (pigs): PGF2a
Mare: oxytocin
Cryptorchidism
Serial injections of hCG
Anabolic steroids (Test.)
Equine: ↑ athletic performance
Dogs and cats: aplastic anemia and myeloproliferative disease
Ex: stanozolol, nandrolone, boldenone undecylenate
Stanozolol (BANNED)
↑ erythropoiesis, arouse appetite, promote weight gain in equine
Nandrolone (BANNED)
Improve weight gain and appetite in equine
Finasteride
Irreversible 5a reductase inhibitor
Blocks conversion of Testosterone to 5a dihydrotest.
Treats benign prostatic hyperplasia (apoptosis)
