Lecture 66 Flashcards
Growth hormone is also called
somatotropin
Growth hormone is the number 1 most important thing for
GROWTH (bones, muscle, etc)
Growth hormone (somatotropin) is a single chain _______
polypeptide (AA sequence varies by species)
GH secretion is described as
Pulsatile (burst of release every 2-4 hrs)
GH secretion: _______ pattern in fish and mammals
circadian (depends on species nocturnal pulses)
Sexual dimorphism in GH secretion for _______ (3 groups of animals)
Humans, rodents, fish
Growth hormone (somatotropin): Large, nocturnal pulses in _______, more sustained secretion in _______
males; females
Growth hormone (somatotropin): (Decreases/ increases) with age
decreases
_______ explains the “growth spurt” at puberty
Growth hormone (somatotropin) increases in frequency and magnitude of pulses
Regulation of GH secretion: Stimulators of GH
GHRH, Decreased glucose, Decreased FFA, Increased AA (ex: arginine), Puberty (estrogen/testosterone)
Does Hypoglycemia/fasting/starvation stimulate or inhibit GH
STIMULATE
Regulation of GH secretion: Inhibitors of GH
Somatostatin, Increased glucose, FFA, GH, Obesity, Somatomedins (IGFs)
_______ 3 stimulators of GH are in the “nutrient regulation” category
Decreased glucose, Decreased FFA, Increased AA (ex: arginine)
why is nutrient regulation important
we need building blocks for growth (decrease in nutrients is stimulatory because that means they’ve been used up)
How can GH be its own inhibitor
negative feedback (prevent us from making too much)
Somatomedins (IGFs): _______ is it? _______ does IGF stand for?
hormones produced by the liver that stimulate somatostatin from Hypothalamus; IGF= insulin-like growth factor
where do Somatomedins (IGFs) inhibit
at anterior pituitary
GH has metabolic actions on (4)
liver, muscle, adipose, bone
_______ synthesis carbohydrate and lipid _______
linear and organ; protein; metabolism
Actions of GH: Direct anabolic actions of GH (GH acting on self)
Increased Ca absorption from gut, P reabsorption from kidney, protein synthesis in liver
Define anabolic and catabolic
anabolic is build up; catabolic is break down
Actions of GH: Indirect anabolic actions via somatomedins (insulin-like growth factors - IGF) _______ are the IGF’s involved
IGF-1 (somatomedin C); IGF-2(somatomedin A); stimulated by GH**
Actions of GH: Indirect anabolic actions via somatomedins (insulin-like growth factors - IGF) _______ do these lead do (3)
Increased lean muscle mass, linear bone growth, organ size/function
Where are IGF 1 and 2 made _______ receptors do they act on
made in liver; act on receptors similar to insulin receptors (TYROSINE KINASE activity)
Explain the general process of indirect anabolic actions via somatomedins (insulin-like growth factors - IGF)
GH stimulates IGF or Somatostatin then IGF or somatostatin then acts on tissue
Direct catabolic effects of GH: Increased _______ in liver
gluconeogenesis (break down to make glucose)
Direct catabolic effects of GH: Increased gluconeogenesis in liver helps maintain _______ within normal range
blood glucose
Direct catabolic effects of GH: Increased gluconeogenesis in liver Maintains blood glucose within normal range _______ decreases because of this? _______ results because of the decrease
Decreases glucose uptake in skeletal muscle has temporary insulin resistance (means the glucose is available for other organs)
Direct catabolic effects of GH: Increase _______ in adipose tissue
lipolysis
Direct catabolic effects of GH increases lipolysis in adipose tissue _______ 2 things does this lead to When there is a release of FFA into blood. _______ does FFA bind to?
Release of FFA into blood, Increased formation of ketones
_______ does it turn into?
Albumin; NEFA’s
An increase in ketone bodies can lead to
metabolic acidosis
Abnormal secretion of GH: A deficiency/lack of GH secretion leads to
dwarfism
_______ are the 2 types of dwarfism we discussed
pituitary dwarfism & disproportional dwarfism
_______ is pituitary dwarfism
autosomal recessive common in GSD
_______ is disproportional dwarfism
shortened long bones common in dachshunds, corgis, basset hounds
which of the following will STIMULATE GH secretion
Decreased FA’s
Excessive GH secretion leads to
acromegaly
Where/ how do we see acromegaly (excessive GH secretion) in cats
Pituitary tumor in cats
Excessive GH secretion (acromegaly) in dogs causes
Increased progesterone during diestrus in dog
Increased progesterone during diestrus in dog _______ type of dogs experience this
ALL intact females go through a period after estrus when progesterone increases, regardless of being pregnant or not
Increased progesterone during diestrus in dog and _______ does this lead to
High progesterone which antagonizes insulin, stimulates GH; LEADS to : Insulin resistance
_______ will inhibit ADH
Hypervolemia
_______ are the 2 hormones released from posterior pituitary
Antidiuretic hormone (ADH;vasopressin/arginine vasopressin) and Oxytocin
ADH and Oxytocin are classified as _______ kind of hormone
neuropeptide (hormone made in neurons)
_______ hormone is synthesized primarily by neurons in supraoptic nuclei of hypothalamus
Antidiuretic hormone (ADH;vasopressin/arginine vasopressin)
_______ is the peptide precursor for ADH
prepropressophysin
_______ makes up prepropressophysin
ADH, neurophysin 2, signal peptide
_______ hormone is synthesized primarily by neurons in paraventricular nuclei of hypothalamus
Oxytocin
_______ is the Peptide precursor for oxytocin
prepro-oxyphysin
_______ makes up prepro-oxyphysin
oxytocin, neurophysin 1, signal peptide
Hormones released from posterior pituitary: Secretion of _______ in posterior pituitary
vesicles
Hormones released from posterior pituitary: Action potential from cell body in _______
hypothalamus
Hormones released from posterior pituitary: _______ does the AP from the hypothalamus cause to happen
Causes Calcium to enter nerve terminal, and exocytose vesicles where they’ll be picked up by the capillary plexus
Hormones released from posterior pituitary : After each hormone is synthesized _______ steps does it go through (3)
Golgi removes signal peptide and packages pro-hormone into vesicles, Neurophysin will be removed as it travels down the axon to the posterior pituitary, Ready to be released once in posterior pituitary
Stimulation of oxytocin secretion: _______ is the main stimulus for oxytocin? Where are the receptors?
Major stimulus is suckling; Sensory receptors on myoepithelial cells of alveoli in mammary gland
_______ does suckling result in?
Results in milk let-down
Other than suckling, _______ is the other stimulus for oxytocin
Stimulation of cervix by fetus
Stimulation of oxytocin secretion: Stimulation of cervix by fetus results in
Results in uterine contractions (Oxytocin acts on smooth muscle of uterus)
T/F Uterine contractions is an example of negative feedback
F; positive feedback
Oxytocin effect on males
acts on testes, epididymis and prostate to aid in sperm movement and ejaculation
Regulation of ADH secretion: Stimulators (7)
Increased plasma osmolarity, Decreased blood volume(hypovolemia), Decreased blood pressure, Pain, Nausea, Hypoglycemia, Nicotine, opiates
Stimulation of ADH results in _______ of water
REABSORPTION
Regulation of ADH secretion: Inhibitors (5)
Decreased plasma osmolarity, Increased blood volume(hypervolemia), Increased blood pressure, Ethanol, Glucocorticoids
Regulation of ADH secretion: _______ happens when plasma osmolarity is increased
increase water reabsorption; increase urine concentration
Regulation of ADH secretion : _______ happens when blood volume decreases (ex: hemorrhage)
stimulates baroreceptors
decreases blood pressure
Loss of _______ percent of ECF will result in a decrease in blood volume (hypovolemia)
10
Regulation of ADH secretion: How does pain stimulate ADH
We actually don’t know, we know that pain stimulates the hypothalamus
Regulation of ADH secretion: How does nausea stimulate ADH
there is a loss of fluids
Regulation of ADH secretion: How does hypoglycemia stimulate ADH
weak stimulus- probably acting with osmotic triggers
Regulation of ADH secretion: How does Glucocorticoids inhibit ADH
they decrease renal sensitivity to ADH
_______ 2 areas of the nephron are water permeable
Distal convoluted tubule and collecting duct are permeable to water (water can be reabsorbed into blood)
In the nephron, under the influence of _______ water can be reabsorbed into blood
UNDER THE INFLUENCE OF ADH
_______ are the 2 main actions of ADH
kidney and vascular smooth muscle
_______ ADH-V receptor does the kidneys use? Vascular smooth muscle?
Kidney and V2 receptor (adenylyl cylase and cAMP) VSM and V1 receptor; increases BP
Vascular smooth muscle contraction causes constriction of
arterioles
How does ADH affect the kidney and free water absorption
Increase water permeability of principal cells in distal convoluted tubules and collecting ducts of kidney
_______ are the 3 main abnormal ADH secretion diseases we discussed in class
Central diabetes insipidus; Peripheral or nephrogenic diabetes indipidus; Syndrome of inappropriate ADH secretion
_______ disease is caused by a lack of ADH secretion likely due to a head injury
Central diabetes insipidus
_______ disease is caused by the posterior pituitary being normal, but principal cells in collecting duct are unresponsive to ADH
Peripheral or nephrogenic diabetes insipidus
_______ disease is caused by a defect in V2 receptor or G protein/ andenylyl cyclase
Peripheral or nephrogenic diabetes insipidus
_______ syndrome is related to excess ADH released from posterior pituitary or not at all (Ex: disorders in brain, certain medications)
Syndrome of inappropriate ADH secretion (there is no feedback inhibition)
Central diabetes insipidus: _______ happens to ADH, Urine, ECF osmolarity
ADH decrease; Urine increase; ECF osmolarity increase (something is inhibiting ADH release)
Peripheral or nephrogenic diabetes insipidus: _______ happens to ADH, Urine, ECF osmolarity
ADH increase; Urine dilute; ECF osmolarity increased
Syndrome of inappropriate ADH secretion: _______ 3 things result from this
Hypervolemia and hyponatremia; Urine very concentrated
