Pituitary Flashcards
what hormones are produced by the hypothalamus?
GHRH, SST, TRH, CRH, GnRH
what hormones are produced by the pituitary gland?
GH, TSH, SCTH, FSH, LH
what hormones are produced by the anterior pituitary gland?
GH, TSH, SCTH, FSH, LH, ACTH
what hormones are produced by the posterior pituitary gland?
vasopressin and oxytocin
how is the synthesis of each hormone stimulated?
- female and male infertility
how is the synthesis of each hormone suppressed?
- endometriosis
- prostate cancer
- central precious puberty
- continuous treatment with GnRH agonist –> suppression of gonadotropin release
- controlled ovarian hyperstimulation
where is HGRH, SST –> GH produced?
peripheral tissues
where is TRH –> TSH produced?
thyroid
where is CRH –> ACTH produced?
adrenal cortex
where is GnRH –> FHS,LH produced?
gonads
what is GH (growth hormone)?
- it is a single-chain protein hormone
- it activates receptors associated with JAK/STAT pathway
what is THG,FSH,LH (thyroid stimulating hormones)?
- dimeric protein hormones sharing common alpha chain
- activate GPCRs
what is ACTH (adrenocorticotropic hormone)?
- single chain peptide
- activates GPCR
what does FSH do in women?
- directs ovarian follicle development
- stimulates conversion of testosterone to estrogens
what does FSH do in men?
- regulates spermatogenesis
- stimulates the conversion of testosterone to estrogens
what does LH do in women?
- stimulate androgen production in the follicular phase
- controls estrogen and progesterone production in the luteal phase
what does LH do in men?
- stimulate androgen production
what is hCG?
- produced in placenta during pregnancy
- nearly identical to LH
- controls estrogen and progesterone production during pregnancy
what is the structure of FSH, LH, and hCG?
- are all heterodimeric proteins
– share same alpha-chain
– distinct b-chain confers receptor specificity
– beta chains of hCG and LH are identical - administered subQ or IM inj
- HL: 10-40 hrs
what are the preparations used clinically?
- menotropins
- urofollitropin
- follitropin a and b
- lutopin a
- hCG
- choriogonadotropin a
describe menotropins?
- hMG (human menopausal gonadotropin)
- 1st commercial gonadotropin product
- extracted from postmenopausal women urine
- mix of FSh and LH
- lower potency than purified LSH or LH
describe urofollitropin?
- uFSH
- FSH purified from urine of postmenopausal women
- LH activity removed during purification
describe follitropin a and b?
- recombinant forms of FSH
- identical in aa sequence with FSH
- differ from each other and uFSH in carb chains
- more expensive than uFSH
describe lutropin a?
- recomb form of LH
- d/c’d from market in 2012 in US
- approved combo use with follitropin a for stimulation of follicular development in infertile women with LH deficiency
descrie hCG?
- extracted and purified from urine of prego women
describe rhCG?
- recomb form of hCG
what drugs are gonadotropins?
- menotropins
- urofollitropin
- follitroin a and b
- lutropin a
- hCG
- rhCH
what drugs are GnRH agonists?
- gonadorelin
- goserelin
- histrelin
- leuprolide
- nafarelin
- tritorelin
what drugs are GnRH antagonists?
- ganirelix
- cetrorelix
- abarelix
- degarelix
describe how female infertility leads to stimulation or how it can be stimulated?
- injected IV in pulsatile fashion using battery powered pump
- less likely to cause multiple pregnancies/ ovarian hyperstimulation syndrome
- not used due to inconvenience/cost
describe how male infertility leads to stimulation or how it can be stimulated?
- men with hypothalamic hypogonadotropic hypogonadism
- pulsatile inj. using portable pump
- treatment with hCG/hMG more favored
describe controlled ovarian hyperstimulation in suppression?
- suppression of endogenous LH surge that could cause premature ovulation
- daily subQ inj of leuprolide or daily nasal app of nafarelin
describe endometriosis in suppression?
suppression of gonadotropin release –> suppression of ovaries –> reduced production of estrogen/progesterone
describe prostate cancer in suppression?
combo with androgen receptor antagonist –> reduction of testosterone levels/effects
what are GnRH’s analogs?
- goserelin, histerelin, leuprolide, nafarelin, triptorelin
- D-aa @ position 6
- ethylamide sub for glycine @ position 10
- more potent/ longer acting than GnRH/gonadorelin
describe the use of pulsatile secretion of GnRH?
stimulate production/release of LH&FSH only when secretion is pulsatile
why do we use continuous admins of GnRH?
- to prevent premature endogenous surge of LH and these effects can be blocked by this receptor GnRH antagonist
- suppress the release of early surge
what happens if we use GnRH and its analog in pulsatile secretion?
in pulsatile use of both GnRH and its analog, the secretion of GnRH is mimicked (via IV Q1–4h)
what happens when we have nonpulsatile administration of either GnRH or its analog?
it inhibits the release of FSH & LH in both women and men resulting in hypogonadism , which is not good
