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pt > L 15 pituitary hormones 1 > Flashcards

L 15 pituitary hormones 1 Flashcards

1
Q

pituitary glands

A

-the master gland
-hypophysis
-size of a pea

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2
Q

anterior pituitary hormones: growth hormone

A

-GH
-prolactin
-single chain protein hormones
-activate receptors associated with JAK/STAT pathway

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3
Q

anterior pituitary hormone: thyroid stimulating hormones

A

-TSH, FSH, LH
-dimeric protein hormones sharing a common alpha chain
-activates GPCRs

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4
Q

anterior pituitary hormones: adrencorticotropic hormones

A

-ACTH
-single chain peptide
-activiates a GPCR

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5
Q

gonadotropins and human chorionic gonadotropin

A

-follicle stimulating hormones (FSH)
-luteinizing hormones (LH)
-human chlorionic gonadotropin (hCG)

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6
Q

follicle stimulating hormones (FSH)

A

-in women: Directs ovarian follicle development and Stimulates the conversion of testosterone to estrogens
-in men: Regulates spermatogenesis and Stimulates the conversion of testosterone to estrogens

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7
Q

luteinizing hormone

A

in women: Stimulates androgen production in the follicular phase and Controls estrogen and progesterone production in the luteal phase
-in men:Stimulates androgen production

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8
Q

human chorionic gonadotropin

A

-Produced in the placenta during pregnancy
-Nearly identical with LH (binds LH receptors).
-Controls estrogen and progesterone production during pregnancy

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9
Q

structures of gonadotropins

A

-FSH, LH, and hCG are all heterodimeric proteins.
 Shares the same α-chain.
 Distinct β-chain confers receptor specificity.
 The β-chains of hCG and LH are nearly identical.
-Administered subcutaneous or intramuscular injection.
-Half-life: 10 – 40 hrs (dependent on the preparation and route of injection

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10
Q

preparations used clinically: menotropins

A

-Human menopausal gonadotropins (hMG)
-First commercial gonadotropin product
-Extracted from the urine of postmenopausal women.
-Mixture of FSH and LH
-Lower potency than purified FSH or LH.

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11
Q

preparation used clinically: urofollitropin (uFSH)

A

-FSH purified from the urine of postmenopausal women.
-LH activity is removed during purification

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12
Q

preparations used clinically: follitropin alpha and follitropin beta

A

-Recombinant forms of FSH
-Identical in amino acid sequence with FSH.
-Differ from each other and uFSH in carbohydrate chains.
-Considerably more expensive than uFSH

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13
Q

preparations used clinically: lutropin alpha

A

-recombinant form of LH
-Approved for use in combination with follitropin α for stimulation of follicular development in infertile women with LH deficiency.
-Discontinued from US market in 2012

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14
Q

preparations used clinically: hCG

A

Extracted and purified from the urine of pregnant women

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15
Q

preparations used clinically: choriogonadotropin alpha (rhCG)

A

recombinant form of hCG

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16
Q

clinical uses -ovulation induction

A

-in women with anovulation secondary to hypogonadotropic hypogonadism, polycystic ovary syndrome, etc.
 High cost
 Needs close monitoring during the administration.
 Reserved for patients who fail to respond to other treatments (Ex. clomiphene).
-Controlled ovarian hyperstimulation in reproductive technology procedures
-Protocols are based on the physiology of a normal menstrual cycle.

17
Q

ovulation induction protocol

A

1)FSH preparations (hMG, uFSH) during the follicular phase.
 To prevent premature endogenous surge in LH, the effects of endogenous GnRH need to be blocked by continuous administration of GnRH or GnRH receptor antagonist.
2. Administration of hCG –> ovulation –> insemination or oocyte retrieval
3. Hormonal support during the luteal phase typically by exogenous progesterone.

18
Q

clinical uses- male infertility

A

-Most of the symptoms of hypogonadism in men can be treated with exogenous androgens.
-However, treatment of infertility in hypogonadal men requires LH and FSH.
-Protocol
1. Injection of hCG for 8-12 weeks (initial phase)
2. Injection of hMG for months
-Introduction of intracytoplasmic sperm injection (ICSI) reduces significantly the minimum requirement of spermatogenesis.

19
Q

adverse effects of ovarian hyperstimulation syndrome

A

-Occurs in 0.5-4% of patients.
-Overproduction of estrogen and progesterone –> vascular hyperpermeability
-Ovarian enlargement, ascites, hydrothorax, and hypovolemia

20
Q

adverse effects of mulitple pregnancy

A

15-20% when ovulation induction is used. (1% in general population)

21
Q

gonadrotropin releasing hormone

A

-Decapeptide hormone secreted by neurons in the hypothalamus.
-Binds to GPCRs on the plasma membranes of gonadotrope cells in the anterior pituitary.
-Gonadorelin
 Acetate salt of synthetic human GnRH
 Half-life: 4 mins (intravenous), 3 hrs (subcutaneous)

22
Q

synthetic analogs of GnRH

A

-Goserelin, histrelin, leuprolide, nafarelin, triptorelin
-D-amino acid at position 6
-Ethylamide substituted for glycine at position 10 (except nafarelin)
-More potent and longer-lasting than GnRH and gonadorelin

23
Q

pulsatile secretion of GnRH

A

-GnRH stimulates the production and release of LH and FSH only when its secretion is pulsatile.
-In the pharmacological use of GnRH and its analog, the pulsatile secretion of GnRH is mimicked.
 Intravenous administration of every 1-4 hrs.
-Nonpulsatile administration of GnRH or GnRH analogs inhibits the release of FSH and LH in both women and men, resulting in hypogonadism.

24
Q

clinical uses stimulation: female infertility

A

-Injected intravenously in a pulsatile fashion using a portable battery-powered programmable pump.
-Less likely than gonadotropins to cause multiple pregnancies and the ovarian hyperstimulation syndrome.
-Not commonly used due to the inconvenience and cost.

25
Q

clinical uses stimulation: male infertility

A

-In men with hypothalamic hypogonadotropic hypogonadism.
-Pulsatile injection using a portable pump (for months).
-Treatment with gonadotropins (hCG and hMG) is more favored.

26
Q

clinical uses; suppression

A

-Continuous treatment with a GnRH agonist
- Suppression of gonadotropin release
-Central precocious puberty

27
Q

Controlled ovarian hyperstimulation: suppression

A

 Suppression of endogenous LH surge that could cause premature ovulation
 Daily subcutaneous injection of leuprolide or daily nasal application of nafarelin

28
Q

endometriosis: suppression

A

 Suppression of gonadotropin releases  suppression of ovaries –> reduced production of estrogen and progesterone

29
Q

prostate cancer: suppression

A

 Combination with an androgen receptor antagonist –> reduction of testosterone levels and effects

30
Q

GnRH receptor antagonist

A

-synthetic decapepetides that function as competitive antagonist
-controlled ovarian hyperstimulation (ganirelix, centrorelix)
-advanced prostate cancer

31
Q

GnRH receptor antagonist: synthetic decapepetides that function as competitive antagonist

A

-Ganirelix
-Cetrorelix
-Abarelix
-Degarelix

32
Q

GnRH receptor antagonist: controlled ovarian hyperstimulation

A

-Produce an immediate antagonist effect –> shorter duration of treatment
-Lower risk of ovarian hyperstimulation syndrome

33
Q

gonadotropins

A

-Menotropins
-Urofollitropin
-Follitropin α and follitropin β
-Lutropin α
-hCG
-Choriogonadotropin

34
Q

GnRH agonist

A

 Gonadorelin
 Goserelin
 Histrelin
 Leuprolide
 Nafarelin
 Triptorelin

35
Q

GnRH antagonist

A

 Ganirelix
 Cetrorelix
 Abarelix
 Degarelix

pt (17 decks)

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