Unit 4 Flashcards
specificity of hormone actions
only target cells have receptors
higher concentration in blood to some cells
conversion to a more active form in the target tissue
amino acid derivative properties
small
hydrophilic/lipophobic
stored in vesciels and released by exocytosis
types of amino acid derivatives
EP, NE, dopamine, thyroid hormone
thyroid hormone properties
small
hydrophobic/lipiphilic
escape from cells as they are made, stored bound to plasma proteins
peptide and protein hormone properties
fairly large
hydrophilic/lipophobic
stored in vesicles and released by exocytosis
*formed as larger precursor proteins that are cleaved to form the active hormone
steroid hormones are always derived from
cholesterol
steroid hormone properties
hydrophobic/lipophilic
act on intracellular receptors
escape from cells as they are made, stored bound to plasma proteins
steroid and thyroid hormones stored bound to proteins increases
half-life
why can’t steroid and thyroid hormone be stored in cells
they cross membranes
activation of second messenger systems
- transer information into the cell
- signal amplication
GHRH increases the release of
GH
somatostatin decreases the release of
GH
ATP acting in cAMP activates __ which increases __ release
PKA, GH
TRH stimulates
phospholipase C
phospholipase C cleaves PIP2 into
IP3 and DAG
DAG increases
TSH production
IP3 increases
TSH release
* acts on ER to release Ca++ to stimulate TSH release
both DAG and IP3 are described as
second messangers
insulin acts through a
tyrosine kinase
insulin binds to
alpha subunits
* causes autophosporylation of beta-subunit
calcium is an important
2nd messenger
what carries hypothalamic harmones to the anterior pituitary
hypophysial portal vein
what is the primary plexus of anterior pituitary
capillaries that take up GHRH, TRH
secondary capillary plexus
2nd capillary bed
* in series with primary plexus
* takes up hormones GH, TRH
what are the 6 anterior pituitary hormones
FSH and LH, GH, TSH, prolactin, ACTH
function of GH
- cartilage and bone growth
- protein metabolism
- carbohydrate metabolism
- lipid metabolism
growth hormone deficiency in children
short, but normal proportions
* treatment: give GH injections
high growth hormone in children
gigantism
high growth hormone in adults
agromegaly
* increase of gorwth of bone where the growth plate does not close off - bones in face
prolactin function
increase breast development and milk production
what stimulates prolactin release
estrogen and TRH
what inhibits prolactin release
dopamine, estrogen and progesterone
what are the two main hormones of the posteiror pituitary
ADH and oxytocin
what are the two main hormones of the posteiror pituitary
ADH and oxytocin
function of oxytocin
milk release, contraction of uterin emsucle for birth
ADH function
increase H2O reabsorption in distal tubule and collecting duct
alpha cells release
glucagon
beta cells release
insulin and amylin
amylin
inhibits the GI tract
satiety factor
delat cells release
somatostatin
* inhibits glucagon and insulin secretion
* release increases after a meal
gamma PP cells release
pancreatic polypeptide
* inhibits exocrine pacnreas secretion of enzymes
what is released with insulin
C-peptide, same amount released
importance of C-peptide
can be measured as a marker for insulin
GLUT 1
transport of glucose across the blood brain barrier
GLUT 2
kidneys - glucose reabsorption, liver - glucose uptake or release, pancreas - beta cells (regulate insulin release)
GLUT 3
on neurons
GLUT 4
skeletal and cardiac muscle, adipose (fat) cells
effects of insulin on carbohydrates
- insulin stimulates glucose uptake into skeletal muscle, cardiac muscle, and adipose cells but not the brain
- stimulates glycogen synthesis
- inhibits gluconeogenesis
what is the only insulin regualted glucose transporter
GLUT 4
insulin inhibits
hormone-sensitive lipase, lipoprotein lipase
insulin can both stimulate and inhibit
lipoprotein lipase
proteins
- increase amino acid uptake into cells
- increases protein synthesis
- decrease protien breakdown
what stimulates insulin secretion
- glucose
- amino acids
- free fatty acids
- ACh
- GIP
- GLP-1
what stimulates glucagon secretion
- amino acid s
- NE, EP
- ACh
what inhibits glucagon secretion
- glucose
- insulin
- somatostatin
- free fatty acids
function of thyroid hormones
CNS development
Growth and metabolism
Basal metabolic rate
hashimoto’s disease
main cause of hypothyroidism in the US
* body makes antibodies against the thyroid gland
symptoms of hypothyroidism
decreased BMR
weight gain
intolerance to cold
fatigue
graves’ disease
autoimmune - antibodies activate TSH receptors
