GH Podcast Flashcards
Control of growth via hormones
major stimulator of
GF within specific tissues, such as
Thyroid Hormone is essential for
Permissive to
Gonadal estrogen in both sexes important for
Insulin for
Cortisol for
def/excess leads to
GH (or somatostatin) via circulating IGF1
postnatal somatic growth
IGF1, NGF, EGF
normal CNS develop, GH sec/receptors
GH actions
pubertal growth spurt, closing epiphysis, GH sec
normal growth
normal growth, inc GH release
inhibited growth
Fetal growth
independent of
Depends on
Diabetic moms have
Neonatal growth- 2 yrs
rate of growth is fastest in
GH
Insulin, IGF2
larger infants, inc glucose/insulin
independent of GH
utero, neonates
Prepubertal growth rate
Pubertal growth spurt caused by
comes from
high, adult levels of estadiol results in
Growth in adults
fast initially, slows until puberty
inc estradiol
aromatized androgens in M/F, in combo w inc GH/IGF1
epiphyseal closure (stop grow)
none
Hormonal control of growth
Prenatal (2 + others)
Juvenile (5)
Adolescent-Puberty (1 + other)
Insulin, IGF2
GH, IGF1, TH, Insulin, Cortisol
Sex steroids, juvenile hormone
Most abundant hormone in AP
Structurally similar to
____ forms circulate
can be bound to
Plasma conc ___ in the day
GH levels reflect growth if integrated
clinically assess growth rate via
GH
Prolactin and hPL
several
receptor fragment (GHBP)
varies widely
over time (urine samples)
IGF levels
GH receptor
GH binds and forms
activates _____, which acivates ______
Activated STAT dimerizes, tanslocates to nucleus and binds _______ on DNA
this initiates trxn of ____
also activates other pathways
cytokine subtype of tyrosine kinase receptor
homodimer
JAK kinase, cytoplasmic STAT TF
GH response element
target genes (IGF1, IGFBP)
MAP kinase, PI3
Direct actions of GH
Affects _____ metabolism by ______
Inc
dec
intermediary, opposing insulin
lipolysis, glucose, gluconeogenesis
glucose uptake in muscle/adipose tissue
Indirect actions of GH
In bone/splanchnic organs, inc
mediated by
growth/protein synthesis
IGF1
IGF1 synthesized and released by, in response to
structually similar to
receptors similar to
Circulating pool maintained by
circulates in blood
Plasma levels ____ w growth rate
liver, GH
proinsulin
insulin receptors
liver
bound to carrier protein (IGFBP) to inc 1/2L
directly correlate
Action of IGF1
Stimulates ___ prior to epiphyseal closure
Exerts ____ on GH
inhibits ______
stimulates ______ release, inhibits ___ release from hypothalamus
cartillage/long bone growth/growth of splanchnic organs
NFA
GH from AP
GHIH (Somatostatin), GHRH
GH can be affected by
A S A S I H
AA (arginine) Sleep Age stress intense exercise Hypoglycemia
GH deficiency prepubertally
if dec pituitary GH only
dec all AP hormones
defect in expression of GH receptors
this presents with
dwarfism
sexual ateliotic dwarf
panhypopituitary dwarf
Laron dwarf
normal/high GH
low IGF1
GH def in adulthood
h i d m e
hypogly inc body fat dec protein muscle weakness exhaustion
Tests for GH secretion
GH excess characterized by
cause
prepubertally leads to, assc w
post pubertally
other sx
Tx
Arginine, Insulin induced hypoGly, DA
High plasma IGF1
pituitary hypersecreting tumor
Gigantism- hyperGly, cardiac hypertrophy
acromegaly- cartilage/CT overgrowth, enlarged organs
enlarged nose, insulin resistance, diabetes (inc glucose)
somatostatin analog, removal of tumor
