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Hypothalamus and Pituitary Hormones
Dr. Prinster 1/16/13
60
Pharmacology
Post-Graduate
01/22/2013

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Cards

Term
What are the hormones of the anterior lobe of the pituitary?
Definition
FLAT PEG
FSH
LH
ACTH
TSH
Prolactin
Endorphins
GH
Term
What are the two somatotropic hormones?
Definition
Growth hormone (GH)
Prolactin
(these two hormones are structurally analogous)
Term
Structure of growth hormone (Prinster said this was important)?
Definition
191-amino acid peptide
2-sulfhydryl bridges
Term
What type of receptor releases GHRH?
Definition
G-protein-linked receptor
Increased cAMP levels use stimulatory Gs proteins
Term
What does GH stimulate the synthesis and release of? Where does this product exert negative feedback?
Definition
Insulin-like growth factor (IGF-1) from the liver; IGF is a somatomedin that inhibits the release of GH from the anterior pituitary and GHRH from the hypothalamus
Term
What is a GH secretagogue produced in the stomach?
Definition
ghrelin
Term
How and where does ghrelin act?
Definition
Acts at the GH secretagogue receptor (GHSR) on the anterior pituitary to stimulate GH release and stimulate feeding
Term
What mediates direct effects on somatotrope cells in the anterior pituitary to block secretion of growth hormone?
Definition
SomatoSTATIN inhibits secretion of GH by blocking the response of the anterior pituitary to GHRH.
Term
What receptors respond to somatostatin?
Definition
SSTR2 or SSTR5 receptors
Gi-coupled GPCRs that prevent the release of GH
Term
Physiological effects of GH on adipocytes? On hepatocytes?
Definition
Adipocytes? lypolysis
Hepatocytes? gluconeogenesis
Term
What is the IGF-1 receptor similar to? What receptor "family" does its receptor belong to? Where is the IGF receptor synthesized?
Definition
The insulin receptor
Tyrosine kinase receptor family
Synthesized in the liver
Term
What are the growth hormone mimetics to know?
Definition
Somatropin
Somatrem
Recombinant IGF-1
Term
What is Somatropin?
Definition
Recombinant GH
Term
Who is Recombinant IGF-1 used for? Main side effect of Recombinant IGF-1?
Definition
Patients with mutation to the GH receptor
Main side effect is hypoglycemia
Term
Physiological consequences of growth hormone excess in adults? In children?
Definition
Adults? acromegaly
Children? gigantism
Term
Side effects of GH mimetics in children?
Definition
Side effects are generally rare
Idiopathic intracranial hypertension
Increased incidence of leukemia
Too rapid growth can result in slipped epiphyses or scoliosis
Term
Side effects of GH mimetics in adults?
Definition
Peripheral edema
Carpal tunnel syndrome
(Increased incidence of side effects associated with increased age/obesity)
Term
Two other drugs to know about related to growth hormone?
Definition
Octreotide*
Pegvisomant
Term
What kind of drug is Octreotide*?
Definition
A somatostatin analog
(Peptide, has to be injected)
Term
MOA of Octreotide*?
Definition
Selectively binds two somatostatin receptors SSTR2 and SSTR5, blocking the response of the anterior pituitary to GHRH
Inhibits the secretion of numerous hormones including GH (serotonin, gastrin, vasoactive intestinal peptide, motilin)
Term
Advantage of Octreotide* over natural somatostatin
Definition
Octreotide* has a longer half-life than somatostatin
Term
Adverse effects (short- and long-term) of Octreotide*?
Definition
Short-term: nausea, diarrhea, bloating (diminishes over time), pain at injection site
Long-term: gallstone formation, hypo-/hyperglycemia
Term
MOA of Pegvisomant?
Definition
GH receptor antagonist
Pegvisomant is a mutant of the GH molecule that binds to half of the GH receptor dimer; directly inhibits GH activity and subsequent production of IGF-1
Term
Side effect of Pegvisomant?
Definition
Use caution if liver transaminases are elevated
Term
How are prolactin levels regulated?
Definition
Regulation is inhibitory
Increased secretion is (mainly) the result of decreased dopamine release.
Stimulatory effects on prolactin release through Thyrotropin-releasing hormone (TRH) (less efficacious than dopamine)
Term
What are causes of prolactin excess (hyperprolactinemia)?
Definition
Prolactin-secreting adenoma
Decreased dopamine release
Renal failure
Dopamine receptor antagonists
Term
What are the drugs like that are used to treat hyperprolactinemia?
Definition
All are dopamine D2-receptor agonists.
Dopamine receptor agonists often stop the growth of prolacin-secreting adenomas.
D2 receptors are Gi-coupled receptors, and prevent the release of prolactin-containing granules from the anterior pituitary.
Term
Two drugs to know that treat hyperprolactinemia?
Definition
Bromocriptine*
Cabergoline*
Term
Side effects of Bromocriptine*?
Definition
Nausea & vomiting
Postural hypertension due to vasodilatory effects on renal vascular beds
Nasal congestion, CNS effects (less common)
Term
Advantage of Cabergoline* over Bromocriptine*?
Definition
Similar to Bromocriptine*, but much lower tendency to cause nausea
Term
Three analogs of GnRH? What do they all end in?
Definition
Gonadorelin
Goserelin
Nafarelin (N for Nasal spray)
(-relin)
Term
Advantages over natural GnRH?
Definition
All have D-amino acids at position 6. Substitutions make them more potent and increase their half lives.
Term
How is GnRH released to inhibit FSH and LH release? How is GnRH released to stimulate FSH and LH release?
Definition
When administered in a non-pulsatile manner, FSH and LH are induced.
Pulsatile administration results in the release of FSH and LH from the anterior pituitary.
Term
Reasons to inhibit GnRH release?
Definition
Endometriosis - decreases pain associated with cyclic changes in estrogen levels
Prostate cancer - antiandrogen (Flutamide) along with GnRH reduces testosterone levels as well as surgical castration
Suppression of precocious puberty
Term
Adverse effects of GnRH analogs in women? In men?
Definition
Women:
headache, nausea
lightheadedness
menopause-like symptoms (hot flashes, sweats, headaches)
reduced bone density (long-term use)
CI in pregnancy & breastfeeding
Men:
hot flashes
edema
gynecomastia (due to increased effects of estrogen)
Decreased libido
Descreased bone density
Term
Two GnRH antagonists to know?
Definition
Ganirelix
Cetrorelix
Term
How are Ganirelix and Cetrorelix administered?
Definition
Subcu
Term
MOA of Ganirelix and Cetrorelix?
Definition
Prevent LH surge during ovarian hyperstimulation (competitive antagonists at the GnRH receptor)
Term
Advantages to use of Ganirelix and Cetrorelix over GnRH treatment?
Definition
Shorter duration of administration
Less negative impact on ovarian response to gonadotropin stimulation
No LH or FSH surge (okay to give to somebody with prostate cancer that responds to hormone surge)
Term
Adverse effects of Ganirelix and Cetrorelix?
Definition
Nausea
Headache
Ovarian hyperstimulation syndrome
Term
Physiological effects of FSH in women? Physiological effects of LH in women?
Definition
FSH directs ovarian Follicle development.
LH increases androgen production.
In combination they enhance steroidogenesis.
Term
Physiological effects of FSH in men? Physiological effects of LH in men?
Definition
FSH acts on the Sertoli cells and is the primary regulator of Spermatogenesis in men.
LH acts on the Leydig cells and is the main stimulus for testosterone production.
Term
Two FSH preparations to know?
Definition
Urofollitropin
Recombinant FSH - Follitropin alpha and Follitropin beta
Term
What FSH preparation is extracted from the urine of postmenopausal women?
Definition
Urofollitropin
Term
One LH preparation to know?
Definition
Lutropin
Term
What kind of LH is Lutropin and what is it used with?
Definition
Lutropin is recombinant human LH.
It is only approved for use with Follitropin alpha for stimulation of follicular development in infertile women with profound LH deficiency.
Term
Adverse effects of LH and FSH preparations?
Definition
Ovarian hyperstimulation syndrome:
- ovarian enlargement
- ascites
- hypovolemia
- hemopertioneum (due to ruptured ovarian cyst)
Multiple pregnancies
Headache, depression, edema
Term
What are two hormones of the posterior pituitary?
Definition
Oxytocin
Vasopressin (ADH)
Term
Structurally, how are oxytocin and vasopressin similar and different?
Definition
Both are 9-amino acid peptides with an intrapeptide disulfide crosslink
Oxytocin differs from vasopressin at positions 3 & 8
Term
What drug is used to induce labor and prevent postpartum bleeding?
Definition
Oxytocin (Pitocin)
Term
Adverse effects of Oxytocin (Pitocin)?
Definition
Toxicity due to excessive stimulation of uterine contraction can cause fetal distress, placental abruption or uterine rupture.
Activation of vasopressin receptors leading to fluid retention, heart failure, seizures, or death.
Term
Two vasopressin agonists to know?
Definition
Vasopressin
Desmopressin*
Term
What are Vasopressin's MOAs?
Definition
Vasopressin activates (Gq-coupled) V1 receptors, which are found in vascular smooth muscle and mediate vasoconstriction. Vasopressin also stimulates V2 receptors in the collecting tubules of nephrons to increase water reabsorption. This results in more concentrated urine.
V2-like receptor activity at extrarenal sites regulate the release of coagulation factor VIII and von Willebrand factor.
Term
MOA of Desmopressin*?
Definition
Desmopressin is a long-acting synthetic analog of vasopressin that activates V2 receptors on the renal tubule cells to increase water permeability and resorption. Unlike vasopressin, it has minimal effect on V1 receptors which mediate vasoconstriction.
Term
Side effects of Vasopressin and Desmopressin*?
Definition
Abdominal cramping
Term
Side effects of Vasopressin?
Definition
Increased blood pressure
Arrhythmias
MI
Peripheral ischemia
Term
Therapeutic uses for Vasopressin and Desmopressin*?
Definition
Central (but not nephrogenic) diabetes insipidus (Desmopressin* drug of choice, but both will work)
Desmopressin* at bedtime for nocturnal enuresis
Vasopressin for treatment of esophageal variceal bleeding (through its vasoconstrictive properties)
Term
One vasopressin antagonist to know?
Definition
Conivaptan
Term
MOA of Conivaptan?
Definition
Nonpeptide antagonist at V1 and V2 receptors
Term
Therapeutic use of Conivaptan?
Definition
Can be used to treat hyponatremia (that may be associated with elevated circulating levels of vasopressin)
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