Decreased blood glucose

Decreased blood free fatty acids

increased blood amino acids

starvation or fasting, protein deficiency

trauma, stress, excitement, exercise

Testosterone, estrogen

Deep sleep

GHRH

Ghrelin

increased blood glucose

increased blood free fatty acids

aging

obesity

GHIH/somatostatin

exogenous GH

somatomedins (insulin-like growth factors)

synthetic GHRH

used as a diagnostic evalution of decreased plasma GH

no longer available in the US

GHRH analogue

used to tx HIV lipodystrophy

must monitor IGF-1 and glucose levels during therapy

recombinant IGF-1

used in tx of Laron dwarfism or GH deficiency with neutralizing antibodies

synthetic, long-acting peptide analogue of somatostatin

inhibits GH release

used to tx acromegaly, flushing and diarrhea from carcinoid tumors, carcinoid crisis, diarrhea from vasoactive intestinal peptide-secreting tumors, TSH-producing adenomas

monthly depot

acts a competitive antagonist of the GH receptor

used to treat acromegaly

can cause elevated LFTs, expensive

pts require a yearly MRI to exclude enlarging adenoma

some concern of GH-induced tumorigenesis and accelerated somatotroph adenoma growth

has the most potent IGF-1 reducing potential

dopamine receptor agonist 

inhibits pituitary prolactin release, inhibits lactotroph cell growth

used in tx of amenorrhea and galactorrhea from hyperprolactinemia, acromegaly, Parkinson's disease, PMS, prolactinomas

contraindicated in pts with uncontrolled hypertension

less effective that SRLs, but cheaper and taken orally

preferred tx during pregnancy

dopamine receptor agonist

inhibits pituitary prolactin release

used to treat hyperprolactinemia, prolactinomas

less nausea than other prolactin inhibitor

potentially linked to valvular heart disease

recombinant TRH

stimulates TSH release from pituitary

rarely used clinically

recombinant TSH

stimulates thyroid gland to take up iodide

adjunctive tx of malignant tumor of thyroid gland

used to stimulate radioactive iodide uptake in the tx of thyroid cancer

synthetic form of ACTH

used to dx suspected cases of adrenal insufficiency and to assist in primary vs. secondary insuffiency

if primary, administration will fail to increase plasma cortisol

if secondary, administration will increase plasma cortisol

GnRH analogue

used in dx of hypogonadism or tx to stimulate ovulation

normal response to administraiton indicates functional gonadotrophs

pulsatile form is used to stimulate ovulation

GnRH analogue

used in tx of breast cancer, prostate cancer, endometriosis, precocious puberty, acute intermittent porphyria

may lead to hot flashes, gynecomastia, osteoporosis, transient pain, sexual dysfunction

may initially increase testosterone and estrogen levels, but eventually result in gonadotropin suppression

GnRH receptor antagonists

used to inhibit premature LH sureges in women undergoing controlled ovarian hyperstimulation

results in improved rates of implantation and pregnancy

used in ovulation induction, male hypogonadotropic hypogonadism

may cause ovarian hyperstimulation syndrome

mixed V1/V2 receptor antagonists

used for tx of euvolemic and hypervolemic hyponatremia, SIADH-induced hyponatremia

contraindicated in hypovolemic hyponatremia

requires careful titraiton to avoid overcorrection of hyponatremia

V2 receptor-selective antagonist

used in tx of heart failure