AP hormones Flashcards
GH is secreted via ___ every ____
pulsatile pattern every 2 hrs
Direct GH effects are on
skeletal m., liver, bone, adipocytes
Indirect GH effects
via IGF-1 from the liver
GH actions
diabetogenic effect
1) increases insulin levels in blood
2) increases lipolysis of adipocytes
3) decreases blood glucose levels and utilization
4) causes insulin resistance
GH actions
protein synthesis and organ growth
increases protein synthesis and organ growth
1) uptake of a.a.
2) stimulates synthesis of DNA/RNA
3) mediated by somatomedins
GH actions
linear growth
increases linear growth, mediated by somatomedins
stimulates synthesis of DNA, RNA, and protein
metabolism in cartilage forming cells and chondrocytes proliferation
acromegaly
excess GH
mostly due to GH secreting pituitary adenoma
effects are stage-dependent:
before adolescence = gigantism
after adolescence = periosteal growth plates keep growing, organ size increases, increases in extremities, coarsening of facial features, insulin resistance AND glucose intolerance
treated with somatostatin analogue = OCTREOTIDE, inhibits GH secretion
Prolactin in breast development
during adolescence stimulates mammary gland development
during pregnancy stimulates mammary alveoli development
note: it is an effect in combination with estrogen and progesteron
Prolactin in lactogenesis, two periods of development
Induces synthesis of lactin, casein, and lipids
during pregnancy, high levels of estrogen and progesterone keep prolactin levels low, when E & P drop precipitously after birth, prolactin levels increase sharply and begin lactation
Prolactin and ovulation
suppresses ovulation by inhibiting synthesis and secretion of GnRH
Galactorrhea
prolactin excess
prolactin and infertility
caused by excess prolactin
Destruction of the anterior lobe’s effect on prolactin secretion
obliterated
Destruction of lactopherins on prolactin
obliterated
Destruction of the hypothalamic-hypophyseal portal system on prolactin
prolactin excess- dopamine’s NF effect is obliterated
Destruction of the hypothalamus’ effect on prolactin
increases, no dopamine inhibiting signals
Bromocriptine
dopamine receptors that can be used to prolactin excess
panhypopituitarism
condition of inadequate or absent production of anterior pituitary hormones
caused by problems that affect pit. gland and either reduce or destroy its function OR reduce/destroy hypothalamic secretion of varying pit. releasing hormones
Causes of hypopituitarism
brain damage, pituitary tumors, non-pit tumors, infections
autoimmune disorders, genetic causes, idiopathic causes
pituitary tumors
most pituitary tumors are adenomas, occur spontaneously
functional and non functional
functional- release active hormone excessively
non-functional, releases nothing
Adenoma size
less than 1 cm = microadenoma
more than 1 cm = macroadenoma
multiple endocrine neoplasia type 1
MEN 1
develop in 25% of patients with diagnosed pituitary adenomas
Neuropeptides
ADH and oxytocin
Precursor Neuropeptides
preprossophysin
Oxytocin: prepro-oxyphysin
the amino acid differences between oxytocin and ADH
ADH has a Phe and Arg
Oxytocin has a Ile and Leu
what is the major hormone concerned with regulating body fluid?
ADH
triggers of ADH secretion
1) decreased blood pressure sense by baroreceptors in the carotid sinus and aortic arch –> sensory fibers to hypothalamus
2) decreased pressure sense by atrial stretch sensitive sensory neurons —-> hypothalamus
3) osmolarity above 280 mOsM @ hypothalamic osmoreceptors —> INTERNEURONS to hypothalamus —> hypothalamus
4) Angiotensin II
5) sympathetic stimulation
6) dehydration
that’s three things: atrial stretch decrease, pressure decrease at baroreceptors, and osmolarity above 280 mOsm
which stimulation is ADH secretion most sensitive to?
osmolarity, a 1% change in osmolarity will cause ADH release
ADH receptors in the blood vessels and kidneys
V1 in vessels - vasoconstriction
V2 in kidneys - h20 retention
