4/11 Gonadal Hormones and Inhibitors PHARM Flashcards
Possible pharm targets in the HPG axis (both men and women?)
Hypothalamus: GnRH analogs
Pituitary: FSH, LH, hCG
Gonads: Estrogen, Progesterone, Testicular Androgens
2 functions of testicles?
- spermatogenesis
- testosterone function
in the testes, what do LH and FSH do?
LH –> acts on Leydig cells (testosterone synthesis)
FSH –> regulates Sertoli cells (coordinate spermatogenesis and maturation of spermatocytes)
FSH –> stimulates production and secretion of inhibin by Sertoli cells
What type of drug is Goserelin?
GnRH analog.
Bioavailable, stable (more than native GnRH peptide!)
What would Goserelin (and other GnRH analogs) be used for clinically? (5 things)
- Suppression of estrogen production in hormone-dependent BC
- Suppression of estrogen production in hormone-dependent prostate cancer
- to delay puberty in cases of precocious puberty
- To delay puberty in trans youth who are too young for hormone replacement therapy
- in cases of hypergonadism
Goserelin/GnRH analogs: contraindications?
Pregnancy (Cat D)
Goserelin/GnRH analogs: warnings for use in males?
- Increased risk of diabetes, MI, sudden cardiac death, stroke; monitor blood glucose and for signs/symptoms of CVD during therapy.
- Risk of ureteral obstruction or spinal cord compression (monitor during 1st month of therapy). (unclear why)
Goserelin/GnRH analogs: warnings for use in females?
- Use not recommended in nondiagnosed abnormal vaginal bleeding
- Risk factors for decreased bone mineral density (e.g. chronic alcohol, tobacco, anticonvulsants, corticosteroids).
- Premenopausal women: use nonhormonal contraception during and for 12 weeks after therapy or until menses resume.
- Nursing mothers: not recommended.
Use of pituitary hormones for management of infertility:
LH/hCG – two source of hCG?
(LH is the same as hCG; LH made by pituitary, hCG made by fertilized egg and placenta)
hCG from mare urine = Pregnyl
hCG from bacteria = Ovidrel
FSH: primary use in treatment of infertility?
stimulate ovulation
Steroid receptor: if there is no agonist, what are the 2 states a steroid receptor will exist as?
- in cytoplasm of target cell, associated with multi protein complex (“heat shock complex”)
- Bound to target genes in nucleus and associated with co-repressor complex with innate histone-deacetylase activity
Steroid receptor: in presence of antagonist, what state will receptor exist in?
in presence of an antagonist, receptor is bound to target genes (in nucleus), associated with co-repressor complex with innate histone deactylase activity - may be actively repressing target genes.
Steroid receptor: in presence of agonist, what occurs to activate the target gene??
In presence of hormone, the co-repressor complex is bumped off and target gene is activated.
Estrogens: clinical uses?
- Contraception
- Hormone replacement therapy
- Oncology (anti-estrogens used more than estrogens)
- M to F transgender promotion
Laundry list: effects of estrogens on primary and secondary sex characteristics?
(effects on: ovaries, uterus, vag, cervix, genital dev’t, mammary gland, skin, bone, electrolytes, cholesterol)
- Ovaries : stimulate follicular growth; small doses cause an increase in weight of ovary; large doses cause atrophy
- Uterus: endometrial growth
- Vagina: cornification of epithelial cells with thickening and stratification of epithelium
- Cervix: increase of cervical mucous with a lowered viscosity (favoring sperm access)
- Development and maintenance of internal (fallopian tubes, uterus, vagina), and external genitalia.
- Mammary gland: Promotes ductal outgrowth and branching during puberty and in each mammary regenerative cycle.
- Skin: increase in vascularization, development of soft, textured and smooth skin
- Bone: increase osteoblastic activity
- Electrolytes: retention of Na+, Cl- and water by the kidney
- Cholesterol: hypocholesterolemic effect
(Can lower cholesterol–> protective effect)
Estrogens & contraception:
- how do they effect the HPG axis?
- some formulations also include what?
–Ectopic estrogen treatment mimics the negative feedback on the HPG axis resulting in reduced LH and FSH production.
–Many formulations include progesterone which help to offset unwanted side-effects of estrogens.