Hypothalamic & Pituitary Hormones Flashcards
GH / ____, predominantly required during ___
its effects are medated by ____
GH / somatotropin, predominantly required during childhood
its effects are medated by IGF-1
GH mediates effects via cell surface receptors that activate ____ signaling cascades
GH mediates effects via cell surface receptors that activate JAK/STAT signaling cascades
GH Physiological effects
- Stimulation of longitudinal growth of bones
- Increased bone mineral density
- Increased muscle mass (in GH deficient people)
- Increased GFR
- Stimulation of preadipocyte differentiation into adipocytes
- Anti-insulin actions (hyperglycemia) (decreased glucose utilization & increased lipolysis)
- Development & increased function of immune system
GH deficiency
- Genetic or damage to pituitary or hypothalamus
- Short stature and adiposity (in children)
- Hypoglycemia (unopposed insulin action)
- Criteria for Dx
- A growth rate < 4cm per year, and
- the absence of a serum GH response to two GH secretagogues
Recombinant GH = ____
GH analog = ____
Recombinant GH = Somatropin
GH analog = Somatrem
Clinical use of Somatropin
- Growth failure in children (turner XO, Prader Wili)
-
GH deficiency in adults
- improves metabolic state, increased lean body mass, sense of well-being
-
Hasting in HIV+ pts
- increased lean body mass, weight, physical endurance
-
Short bowel syndrome in pts receiving specialized nutrional support
- improved GI function

Somatotropin/Somatrem AEs in children
- Generally well tolerated
- Scoliosis (during rapid growth)
- Hypothyroidism
- Intracranial hypertension (rare)
- Otitis media (increased risk for Turner Syndrome patients)
- Pancreatitis, gynecomastia & nevus growth
- Diabetic syndrome (chronic use)
Somatotropin/Somatrem AEs in adults
- Peripheral edema, myalgias & arthralgias (hands & wrists especially)
- Carpal tunnel syndrome
- Proliferative retinopathy (rare)
Somatotropin/Somatrem contraindications
- Cytochrome P450 inducer
-
Patients with a known malignancy
- can increase tumor growth
Small number of children with growth failure have ____deficiency
Analog of this?
Small number of children with growth failure have IGF-1 deficiency
Analog: Mecasermin

Mecasermin AEs
- Hypoglycemia (eat 20 min before or after admin.)
- Intracranial hypertension (rare)
- Asymptomatic elevation of liver enzymes (rare)
Small GH-secreting adenomas can be treated with GH antagonists (3)
- GH receptor antagonist → Pegvisomant
- Somatostatin analogs → Octreotide
- Dopamine receptor agonists → Bromocriptine, Cabergoline
(Larger pituitary adenomas require surgery or radiation)
JAK/STAT inhibitor

Pegvisomant (GH receptor antagonist)

describe the somatostain analog
Octreotide
t1/2: 30 x Somatostatin
(inhibits release of GH, TSH, glucagon, insulin, gastrin)

Octreotide clinical applications
- Reduces symptoms from hormone-secreting tumors: acromegaly, carcinoid syndrome, gastrinoma, glucagonoma, nesidioblastosis, watery diarrhea, hypokalemia, achlorhydria syndrome & diabetic diarrhea.
- Localizing neuroendocrine tumors
- Controls bleeding from esophageal varices (vasoconstriction)

Octreotide AEs
- Nausea, vomiting, abdominal cramps, flatulence, steatorrhea (with bulky bowel movements)
- Constipation
- Biliary sludge & gallstones (20-30% pts after 6mo use)
- Sinus bradycardia (25%) & conduction disturbances (10%)
- Vitamin B12 deficiency (long-term use)
- Pain at injection site = common (esp. with long-acting)

Dopamine agonists
which drug has longer half-life?
Bromocriptine, Capergoline
Capergoline t1/2 ~65 h (preferred drug)
Bromocriptine, Capergoline Clinical use
-
Hyperprolactinemia
- Standard treatment. Dopamine agonists shrink pituitary prolactin-secreting tumors, lower circulating prolactin levels, and restore ovulation in ~70% women with microadenomas & ~30% with macroadenomas
-
Acromegaly
- Alone or in addition to surgery, radiation or octreotide admin
Bromocriptine, Capergoline AEs
- Nausea (bromocriptine>cabergoline), headache, light- headedness, orthostatic hypotension, fatigue
- Psychiatric manifestations
- High doses = cold-induced peripheral digital vasospasm
- Chronic high-dosage therapy = pulmonary infiltrates
Effects of Gonadotropins on females
FSH: ovarian follicle development
FSH & LH: ovarian steroidogenesis
Luteal stage of menstrual cycle: estrogen & progesterone production is primarily under control of LH. During pregnancy hCG takes over.
Effects of Gonadotropins on males
FSH: Spermatogenesis, conversion of testosterone to estrogen. Maintains high local androgen concentrations in vicinity of developing cells
LH: Stimulates testosterone production
clinical application of gonadotropins
Infertility
- induce spermatogenesis (men)
- induce ovulation (women)
Follitropin and Urofollitropin
Purified FSH
Lutropin alfa
Recombinant LH
Menotropins
purified FSH and LH extract
Gonadotropins clinical application
-
Male Infertility
- d/t hypogonadism, requires both FSH and LH
- Induce Ovulation
- Expensive and complicated so reserved for when other treatments don’t work
Gonadotropin AEs
- Women
- Ovarian hyperstimulation syndrome
- Multiple pregnancies (15-20%)
- Headache, depression, edema, precocious puberty
- Men
- Gynecomastia
Gonadorelin = ____
Goserelin, Leuprolide, Nafarelin = ____
analogs are more ___ and __-lasting
GnRH: Gonadorelin (4 min)
GnRH Analogs: Goserelin, Leuprolide, Nafarelin (3 hrs)
analogs are more potent and longer-lasting
____ GnRH secretion is required to stimulate release of LH/FSH
Sustained nonpulsatile admin. of GnRH ___ FSH/LH release leading to ____
Pulsatile GnRH secretion is required to stimulate release of LH/FSH
Sustained nonpulsatile admin. of GnRH inhibits FSH/LH release leading to hypogonadism
Continuous administration of GnRH hormone/analog gives ___ response:
First 7 days =
Chronic effects (> 1 week) =
Continuous administration of GnRH hormone/analog gives biphasic response:
First 7 days = agonist response ‘flare’
Chronic effects (> 1 week) = inhibitory action (receptor down-regulation & changes in signaling pathways)
“-relin”/leuprolide STIMULATION effects
-
Male infertility
- d/t hypothalamic hypogonadotropic hypogonadism (pulsatile gonadorelin)
-
Dx LH responsiveness in delayed puberty
- whether it is d/t constitutional delay or hypogonadotropic hypogonadism
- Female infertility: uncommon (inconvenient & costly)
“-relin”/leuprolide more commonly used for SUPPRESSING effects
-
Controlled ovarian hyperstimulation
- leuprolide, nafarelin
- suppress LH surge that can prematurely trigger ovulation
-
Endometriosis
- leuprolide, Goserelin, Nafarelin
- decreased pain
-
Uterine Leiomyomata/fibroids
- Leuprolide, Goserelin, Nafarelin
- reduce fibroid size
-
Prostate Cancer
- Leuprolide, Goserelin
- continuous GnRH Agonist and androgen receptor antagonist = effective as castration in reducing serum testosterone
“-relin”/leuprolide more commonly used for SUPPRESSING effects (continued)
-
Central Precocious Puberty
- leuprolide, nafarelin
- Advanced Breast & Ovarian Cancer
- Treatment of Amenorrhea & Infertility in women with Polycystic Ovary Disease
-
Thinning of Endometrial lining
- Preparation for endometrial ablation procedure in women with dysfunctional uterine bleeding
GnRH pulsatile treatment AE’s
- Headache, light-headedness, nausea, flushing
- Swelling at SC injection site
- HSN dermatitis (long-term admin.)
- acute HSN reactions
- Sudden pituitary apoplexy & blindness (in pts with gonadotropin-secreting pituitary tumor)
GnRH continuous treatment AEs/contraindications
-
Women:
- Menopausal sxs, depression, diminished libido, generalized pain, vaginal dryness & breast atrophy
- Ovarian cysts (generally resolve)
- Reduced bone density & osteoporosis (long treatment)
- Men: Hot flushes, sweats, edema, gynecomastia, decreased libido, decreased hematocrit, reduced bone density, asthenia, & injection site reactions
- Contraindicated: Pregnant or Breast-feeding
“-relix”
Cetrorelix, Ganirelix
GnRH Receptor Antagonists
“-relix” clinical application
Suppress gonadotropin production → Prevent LH surge during controlled ovarian hyperstimulation
Corticotropin, Cosyntropin
ACTH analogs
Corticotropin, Cosyntropin MOA
stimulate adrenal cortex via MC2 receptor (GPCR → increase cAMP) →
secrete glucocorticoids, mineralocorticoids, androgen precursor
Corticotropin, Cosyntropin clinical application
- differentiate between 1° (Addison’s disease) and 2° adrenal insufficiency (inadequate ACTH secretion)
- treat Infantile spasm (West Syndrome)
Corticotropin, Cosyntropin AEs
- simiar to Glucocorticoids
- short term: HTN, hyperglycemia, immunosuppression, psychotic rxns, cognitive impairment
- long term: osteoporosis, weight gain, edema, poor wound healing, ulcers, adrenal suppression
Describe Oxytocin
- Acts on GPCRs → stimulates release of PGs & LTs that augment uterine contraction
- Small dose: increase force & frequency of contractions
- High dose (not good): sustained contractions. Weak antidiuretic & pressor activity (vasopressin R activation)
- Contraction of myoepithelial cells surrounding mammary alveoli → milk ejection
Oxytocin clinical application
- Labor Induction: When early vaginal delivery is required (Rh problems, maternal diabetes, preeclampsia, ruptured membranes)
- Augment Normal Labor: When labor is protracted or displays arrest disorder
- Control of uterine hemorrhage
Oxytocin AEs
- Severe toxicity is rare
-
Excess stimulation of uterine contractions
- Fetal distress, placental abruption, uterine rupture
-
Inadvertent activation of vasopressin receptors
- Excess fluid retention, water intoxication → hyponatremia, heart failure, seizures, death
-
Bolus injections can lead to hypotension
- Administer IV as dilute solution at a controlled rate
oxytocin contraindications
- Fetal distress
- Prematurity
- Abnormal fetal presentation
- Cephalopelvic disproportion
- Uterine rupture predisposition
Atosiban
Oxytocin antagonist
Atosiban is used for treatment of ____ (not in USA)
Atosiban is used for treatment of preterm labor (not in USA)
Vasopressin, Desmopressin
ADH agonists
-
Vasopressin
- released in response to rising plasma tonicity or falling BP
- both antidiuretic and vasopressor activities
-
Desmopressin
- long acting
- minimal V1 action (vascular smooth muscle)
- antidiuretic to vasopressor ratio 4000 x vasopressin
ADH agonist clinical applications
- Diabetes Insipidus DOC
- Vasopressin: Esophageal variceal bleeding & colonic diverticular bleeding
- Desmopressin: Coagulopathy treatment in Hemophilia A and vWF disease

vasopressin agonist AEs
- Headache, nausea, abdominal cramps, allergic reactions
- Overdosage = hyponatremia & seizures
Conivaptan use
- Vasopressin antagonist
- used for pts w/ hyponatremia d/t elevated ADH (SIADH)
- high affinity for V1 and V2