Hypothalamic - pituitary - gonadal axis Flashcards
What are the main releasing hormones
GHRH
CRH
TRH
GnRH
PRH
What are inhibiting hormones
somatostatin (GHIH & TSH)
Dopamine (PIH)
What does growth hormone effects
liver
What does growth hormone produce
somatomedins
What is another name for growth hormone
somatotropin
What is the job of growth hormone
required for normal growth
What are the target tissues for growth hormone
bone
adipose
liver
muscle
growth plates (indirectly- chondrocytes)
What are the growth hormone modulators
somatropin
octreotide
Pregvisomant
What are the indications of somatotropin
GH deficiency
Growth failure
HIV patients with cachexia
What syndromes can cause growth failure
prader-wili
Noonan syndrome
Turner syndrome
What are adverse effects of somatotropin
pain at injection site
edema
arthralgia / myalgia
glucose tolerance
Increased ICP
Which patients should somatotropin NOT be used on
pediatric patients with closed epiphysis (late teens)
What type of hormone is somatostatin
inhibitory
Where is somatostatin made
hypothalamus
What is the MOA of somatostatin
acts on the anterior pituitary
binds to pituitary GHRH receptor
Suppress GH and TSH release
What is the use of somatostatin
Suppress secretions and motility in the GI tract
What are synonyms of somatostatin
GHIH
GHRIH
SRIF
SRIH
What is octreotide
Long acting somatostatin (12hrs - 6wks)
What are indications for Octreotide
Acromegaly
severe diarrhea from carcinoid
bleeding esophageal varices
What are adverse effects of Octerotide
CVS: Bradicardia & conduction issues
GI: Diarrhea, abd pain, nausea, steatorrhea
*gallbladder emptying is delayed and can cause gallstones
What is Pegvisomant
GH receptor antagonist
What is the MOA of Pegvisomant
modified human growth hormone with receptor blocking properties (Inhibits IGF 1 release)
What are indications of pegvisomant
Acromegaly that is refractory to other pharmacological, surgical, or radiologic intervention
What are adverse effects of Pegvisomant
Diarrhea, Nausea, pain, abnormal hepatic function tests
What are the ACTH & ACTH release modulators
Cotricotropin (ACTH)
Cosyntropin
What is the job of corticotropin
stimulates steroid biosynthesis
What is the job of corticotropin releasing hormone
Regulates synthesis and release of ACTH
What kind of drug is Cosyntropin
synthetic ACTH with full biologic potency
What is the MOA of Cosyntropin
Stimulates the adrenal cortex to secrete adrenal steroids, androgenic substances, and small amount of aldosterone
What are the indications of Cosyntropin
Diagnostic tool (ACTH stimulation test) to screen for adrenocorticosteroid deficiency
*Addisons disease
What are adverse effects of cosyntropin
Excess glucocorticoid toxicities
HTN, Peripheral edema, hypokalemia, osteoporosis
What is the normal level of cortisol in the morning
20ug/dL
What is the MOA of GnRH
Gonadotropin-release hormone is released from the hypothalamus and binds to receptors in the anterior pituitary to release gonadotropins
What hormones are gonadotropins
FSH
LH
What type of secretion is essential for gonadotropin release
Pulsatile
What is the result of continuous gonadotropin release
Results in the down regulation of GnRH receptor and suppression of gonadotropin release
What are the indications for gonadotropin production suppression
Prostate cancer
endometriosis and fibroids
precocious puberty
suppressing sex hormones
infertility treatment
What are adverse effects of GnRH in females
generalized menopausal symptoms
Ovarian cyst
What are the adverse effects of GnRH in males
transient increase in testosterone
Decreased libido
hot flashes
gynecomastia
edema
What drugs are FSH-LH release modulators
Leuprolide
Goserelin
Naferelin
Histrelin
What is Leuprolide used for
Treat prostate cancer, breast cancer, endometriosis, uterine fibroids and early puberty
What is Goserelin used for
suppress production of sex hormones, particularly in the treatment of breast and prostate cancer
What is Nafarelin used for
Used in the treatment of endometriosis and early puberty
What is Histrelin used for
Used to treat prostate cancer in adults, will reduce the level of testosterone
Where is prolactin secreted from
anterior pituitary
What is the job of prolactin
stimulate and maintain lactation
decrease libido
What helps regular prolactin
via tonic inhibition by dopamine that increases prolactin secretion
and TRH stimulating the release
What drugs are prolactin release modulators
Bromocriptime
Cabergoline
What is the job of Bromocriptime
dopamine receptor agonist that treats hyperprolactinemia and parkinsons disease
What is the first line agent in the management of prolactinomas and why
cabergoline
has a higher affinity for D2 receptor sites, has less severe side effects, and a more convenient dosing schedule
What are the adverse effects of bromocriptine and cabergoline
headache, dizziness, psychosis, nausea
What hormones are released from the posterior pituitary gland
Oxytocin
Vasopressin
Desmopressin
What is the target tissue for oxytocin
uterus and breast
What is the target tissue for vasopressin (ADH)
Nephron (CT & DC)
Vascular smooth muscle
What are the indications for oxytocin
labor induction
postpartum hemorrhage
What are the adverse effects of oxytocin
hypotension
arrhythmias
Fluid retention
placental abruption/uterine rupture
fetal distress / death
What is the MOA of vasopressin
Stimulates arginine vasopressin receptor
V1- vascular smooth muscle
V2- nephron
What receptor does Desmopressin act on
Selectively V2
Better for central diabetes insipidus
What are the adverse effects of ADH
water intoxication
hyponatremia
headaches
bronchoconstriction
tremor
Which patients should you NOT give desmopressin to
CAD
Epilepsy
asthma
*Children do to seizure risk with nasal spray
What are naturally occurring glucocorticoids
Cortisol
Cortisone
What is the primary action of glucocorticoids
stress hormone
-metabolism
-inflammatory / immune function
Where is CRH released from
hypothalamus
Where is cortisol released from
adrenal cortex
What does cortisol inhibit
CRH
ACTH
What drugs are corticosteroids
betamethasone
cortisone
dexamethasone
hydrocortisone
prednisone
methylprednisolone
triamcinolone
What drugs are mineral corticoids
eplerenone
spironolactone
Fludrocortisone
What is the PK of cortisone
It is a short acting steroid that also have mineralocorticoid activity
liver will convert cortisone to hydrocortisone
What is the PK of hydrocortisone
kidney will convert hydrocortisone to cortisone
What is the MOA of intermediate acting steroids
significantly more affinity to the glucocorticoid receptors
*triamcinolone have no mineralocorticoid effects
What is the PK of prednisone
prodrug converted by liver to prednisone which is then metabolized
What is the MOA of long acting steroids
only bind to glucocorticoid receptors
When are long acting steroids used
high dose injections
lung maturation
What steroid is used in the diagnosis of bushings syndrome
dexamethasone
What steroid is used in primary adrenal insufficiency and congenital adrenal hyperplasia
hydrocortisone
How do betamethasone and dexamethasone help with lung maturation
increases surfactant production
What are naturally occurring mineralocorticoids
aldosterone
What is the job of aldosterone
regulate salt and water metabolism
What is the indication of Fludrocortisone
treatment of Addisons disease and associated mineralocorticoid deficiency
