NST 160 FINAL EXAM QUESTIONS
WITH VERIFIED ANSWERS
How does the BAT Signaling pathway work? - Answer-1) Brain senses cold and
overfeeding which then stimulates the release of norepinephrine
2) Beta 3- AR responds to the increased Norepinephrine. As a result with cAMP, it
signals PKA which then binds to CREB.
3) this then signals for the creation of UCP1 which can then metabolize FA into heat
RA can also induce UCP1 transcription
What is Neuregulin - Answer-A hormone (Nrg4) that decreases lipogenesis in the
liver, released by BAT
What is secreted by constitutive BAT to induce recruitable BAT? - Answer-FGF21,
BMP7
What activates constitutive and recruitable brown fat? - Answer-Cold, Diet induced
thermogenesis, Beta-agonists, and thyroid hormone 3 (T3)
What are mesenchymal stem cells? - Answer-Precursors for brown adipose tissue,
Stem cells. Form constitutive BAT if + and if - then it forms recruitable adipose tissue
along with white adipocytes and preadipocytes.
What factors induce UCP1 transcription - Answer-RA, T3, PPAR. Also Beta3
agonists induce transcription while also stopping UCP1 proteolysis. FA present will
cause UCP1 to do its job
What is the Arcuate Nucleus? (ARC) - Answer-An important nucleus within the
hypothalamus. It holds AgRP/NPY and POMC/CART neurons which are used in
feeding control
What are the two sets of neurons that control feeding and what are their functions? -
Answer-AgRP/NPY and POMC/CART. AgRP/NPY have orexigenic effects, whereas
POMC/CART neurons have anorexigenic effects
What is NPY? - Answer-Neuropeptide Y. Uts a 36 AA peptide. Expression is
stimulated by fasting and suppressed by high-fat feeding. Injections of NPY stimulate
food intake and long-term infusion leads to obesity. Lack of NPY has only a slight
change to phenotypes
What is AgRP? - Answer-Agouti-realted Peptide. Acts as in inverse agonist for MC4
receptors. Co-expressed by NPY neurons in the ARC. INjection stims food intake
and long-term infusion leads to obesity. Loss of MC4 receptors leads to obesity in
humans and mice.
,What are implications of orexins? - Answer-Orexins delay the onset of normal
satiety. Expression is increased in response to severe fasting or hypoglycemia.
Disruption can lead to narcolepsy.
What are the components of the reward system when it comes to orexigenic signals?
- Answer-Opioids, the dopaminergic system, endocannabinoids and serotonin.
Exogenous cannabinoids lead to robust increase in food intake and weight gain.
What is rimonabant and Orlistat? - Answer-Endocannabinoid receptor antagonists
What is CART? - Answer-Cocaine and Amphetamine regulated transcript. It is
greatly increased after cocaine or amphetamines administered to rats. Functions
involve food intake and maintenance of body weight, Expressed by ARC and
decreased during fasting.
What is POMC - Answer-POMC is a precursor for many bio active peptides. In ARC
prohormone convertase 2 generates Alpha-MSH. Work as anorexic signals through
the melanocortin-4 receptor.
What is the interaction between Melanocortin Receptors, Alpha- MSH and AgRP? -
Answer-Alpha- MSH binds to the MC-4R and stabilizes the active conformation
(Agonist). AgRP binds to MC-4R and disrupts the active conformation. It works as an
inverse agonist. If Alpha-MSH is binded to cells there will be anorexic effects if AgRP
is binded there will be orexigenic effects
What is ghrelin? - Answer-It works on AgRP/NGY neurons in the ARC. Realised by
the empty stomach and acts as a potent stimulus to feeding. Lack of sleep increases
Ghrelin
What is GLP1 and 2? - Answer-Glucagon like peptide one and two. Released as a
response to intentistical carbohydrate sensing. Acts via GLP 1 receptors in the
hypothalamus. It strongly stimulates insulin release and inhibits appetite and food.
What is Somatostatin? - Answer-Pancreatic peptide that is realised by delta cells in
response to high plasma glucose and alanine. It inhibits GI Secretions.
What is Pancreatic Polypeptide? - Answer-A member of the PP fold peptide family.
Released by pancreatic islets postprandially in proportion to calories ingested. PP
administration reduces food intake and slows absorption.
What is leptin and its functions? - Answer-Hormones secreted by adipocytes. Leptin
excerpts its anorectic effects in the ARC by down-regulating NPY MCH, orexin, and
AgRP while up regulating Alpha-MSH and cart. Leptin is the strongest feeding
control molecule becuase of its impacts on the other molecules. Activation of mTOR
can increase leptin expression.
How does increased glucose and fatty acid uptake lead to increased leptin
expression? - Answer-Increased uptake leads to enhanced products of the
hexosamine pathway leading to increased glycosylation of proteins, which causes
more leptin expression
, What is AMPK? - Answer-AMP activated protein kinase. Its regulated by the
AMP:ATP ratio. Cellular energy sensor. Known as the master regulator of energy
metabolism. Inactives mTOR. Activates macro autophagy and fatty acid catabolism.
Breaks things down in times of needing energy
What is the interaction between feeding control and AMPK? - Answer-Many of the
signals converge onto AMPK in the hypothalamus. Orexigenic signals increase
AMPK activity while anorexic signals inhibit AMPK.
What is HHS (Hyperglycemic Hyperosmolar State)? - Answer-Symptoms are
polyuria, wt loss, decreased oral intake that leads to confusion, coma, or lethargy.
Caused by insulin deficiency. No ketoacidosis, for unclear reasons.
What are advanced glycosylation products? - Answer-Proteins, lipids, and nucleic
acids that have gone through non-enzymatic glycosylation. At first can be reversed,
but then after the process is complete they can not be reversed. The amount of this
happening is what A1C measures.
What are the results of having a lot of glycosylated products? - Answer-Increased
Vessel wall stiffness, trapping of non glycosylated proteins by cross linked proteins
such as collagen, resistance to proteolytic degradation
What is the polyol pathway? - Answer-The two step pathway to reduce glucose to
sorbitol and fructose. Activated in organs that face diabetic complications. Over
activation of this pathway will cause increased intracellular osmolarity which causes
cell damage.
What is PKC - Answer-Protein kinase C. It can alter the transcription of genes for
fibronectin.
Where does the liver get its supply of precursors for GNG and what are they? -
Answer-Muscles provide lactate, pyruvate, alanine, glutamate, and other amino
acids. TAGs in adipose are broken down into fatty acids and glycerol.
What is the first defense in a state of hypoglycemia? What is the second line of
defense? Third? - Answer-Decreased insulin output by beta cells. The second line of
defence is the release of glucagon from alpha cells. Adrenomedullary epinepherine
is the third line of defense, only used when glucagon is depleated.
What is used in order to prevent prolonged hypoglycemia? - Answer-After 4 hours
cortisol and growth hormone can be used to prevent prolonged hypoglycemia
Where do islets of langerhans get their blood supply and where do they get their
glucose from? - Answer-Blood from splenic, hepatic and superior mesenteric
arteries. Glucose uptake is facilitated by GLUT 2 transporters in canaliculi running
between cells.
What is glut2 and glut4? - Answer-They are glucose transporter proteins that move
glucose across cell membranes. Glut 4 requires insulin to activate it, but glut 2 does
WITH VERIFIED ANSWERS
How does the BAT Signaling pathway work? - Answer-1) Brain senses cold and
overfeeding which then stimulates the release of norepinephrine
2) Beta 3- AR responds to the increased Norepinephrine. As a result with cAMP, it
signals PKA which then binds to CREB.
3) this then signals for the creation of UCP1 which can then metabolize FA into heat
RA can also induce UCP1 transcription
What is Neuregulin - Answer-A hormone (Nrg4) that decreases lipogenesis in the
liver, released by BAT
What is secreted by constitutive BAT to induce recruitable BAT? - Answer-FGF21,
BMP7
What activates constitutive and recruitable brown fat? - Answer-Cold, Diet induced
thermogenesis, Beta-agonists, and thyroid hormone 3 (T3)
What are mesenchymal stem cells? - Answer-Precursors for brown adipose tissue,
Stem cells. Form constitutive BAT if + and if - then it forms recruitable adipose tissue
along with white adipocytes and preadipocytes.
What factors induce UCP1 transcription - Answer-RA, T3, PPAR. Also Beta3
agonists induce transcription while also stopping UCP1 proteolysis. FA present will
cause UCP1 to do its job
What is the Arcuate Nucleus? (ARC) - Answer-An important nucleus within the
hypothalamus. It holds AgRP/NPY and POMC/CART neurons which are used in
feeding control
What are the two sets of neurons that control feeding and what are their functions? -
Answer-AgRP/NPY and POMC/CART. AgRP/NPY have orexigenic effects, whereas
POMC/CART neurons have anorexigenic effects
What is NPY? - Answer-Neuropeptide Y. Uts a 36 AA peptide. Expression is
stimulated by fasting and suppressed by high-fat feeding. Injections of NPY stimulate
food intake and long-term infusion leads to obesity. Lack of NPY has only a slight
change to phenotypes
What is AgRP? - Answer-Agouti-realted Peptide. Acts as in inverse agonist for MC4
receptors. Co-expressed by NPY neurons in the ARC. INjection stims food intake
and long-term infusion leads to obesity. Loss of MC4 receptors leads to obesity in
humans and mice.
,What are implications of orexins? - Answer-Orexins delay the onset of normal
satiety. Expression is increased in response to severe fasting or hypoglycemia.
Disruption can lead to narcolepsy.
What are the components of the reward system when it comes to orexigenic signals?
- Answer-Opioids, the dopaminergic system, endocannabinoids and serotonin.
Exogenous cannabinoids lead to robust increase in food intake and weight gain.
What is rimonabant and Orlistat? - Answer-Endocannabinoid receptor antagonists
What is CART? - Answer-Cocaine and Amphetamine regulated transcript. It is
greatly increased after cocaine or amphetamines administered to rats. Functions
involve food intake and maintenance of body weight, Expressed by ARC and
decreased during fasting.
What is POMC - Answer-POMC is a precursor for many bio active peptides. In ARC
prohormone convertase 2 generates Alpha-MSH. Work as anorexic signals through
the melanocortin-4 receptor.
What is the interaction between Melanocortin Receptors, Alpha- MSH and AgRP? -
Answer-Alpha- MSH binds to the MC-4R and stabilizes the active conformation
(Agonist). AgRP binds to MC-4R and disrupts the active conformation. It works as an
inverse agonist. If Alpha-MSH is binded to cells there will be anorexic effects if AgRP
is binded there will be orexigenic effects
What is ghrelin? - Answer-It works on AgRP/NGY neurons in the ARC. Realised by
the empty stomach and acts as a potent stimulus to feeding. Lack of sleep increases
Ghrelin
What is GLP1 and 2? - Answer-Glucagon like peptide one and two. Released as a
response to intentistical carbohydrate sensing. Acts via GLP 1 receptors in the
hypothalamus. It strongly stimulates insulin release and inhibits appetite and food.
What is Somatostatin? - Answer-Pancreatic peptide that is realised by delta cells in
response to high plasma glucose and alanine. It inhibits GI Secretions.
What is Pancreatic Polypeptide? - Answer-A member of the PP fold peptide family.
Released by pancreatic islets postprandially in proportion to calories ingested. PP
administration reduces food intake and slows absorption.
What is leptin and its functions? - Answer-Hormones secreted by adipocytes. Leptin
excerpts its anorectic effects in the ARC by down-regulating NPY MCH, orexin, and
AgRP while up regulating Alpha-MSH and cart. Leptin is the strongest feeding
control molecule becuase of its impacts on the other molecules. Activation of mTOR
can increase leptin expression.
How does increased glucose and fatty acid uptake lead to increased leptin
expression? - Answer-Increased uptake leads to enhanced products of the
hexosamine pathway leading to increased glycosylation of proteins, which causes
more leptin expression
, What is AMPK? - Answer-AMP activated protein kinase. Its regulated by the
AMP:ATP ratio. Cellular energy sensor. Known as the master regulator of energy
metabolism. Inactives mTOR. Activates macro autophagy and fatty acid catabolism.
Breaks things down in times of needing energy
What is the interaction between feeding control and AMPK? - Answer-Many of the
signals converge onto AMPK in the hypothalamus. Orexigenic signals increase
AMPK activity while anorexic signals inhibit AMPK.
What is HHS (Hyperglycemic Hyperosmolar State)? - Answer-Symptoms are
polyuria, wt loss, decreased oral intake that leads to confusion, coma, or lethargy.
Caused by insulin deficiency. No ketoacidosis, for unclear reasons.
What are advanced glycosylation products? - Answer-Proteins, lipids, and nucleic
acids that have gone through non-enzymatic glycosylation. At first can be reversed,
but then after the process is complete they can not be reversed. The amount of this
happening is what A1C measures.
What are the results of having a lot of glycosylated products? - Answer-Increased
Vessel wall stiffness, trapping of non glycosylated proteins by cross linked proteins
such as collagen, resistance to proteolytic degradation
What is the polyol pathway? - Answer-The two step pathway to reduce glucose to
sorbitol and fructose. Activated in organs that face diabetic complications. Over
activation of this pathway will cause increased intracellular osmolarity which causes
cell damage.
What is PKC - Answer-Protein kinase C. It can alter the transcription of genes for
fibronectin.
Where does the liver get its supply of precursors for GNG and what are they? -
Answer-Muscles provide lactate, pyruvate, alanine, glutamate, and other amino
acids. TAGs in adipose are broken down into fatty acids and glycerol.
What is the first defense in a state of hypoglycemia? What is the second line of
defense? Third? - Answer-Decreased insulin output by beta cells. The second line of
defence is the release of glucagon from alpha cells. Adrenomedullary epinepherine
is the third line of defense, only used when glucagon is depleated.
What is used in order to prevent prolonged hypoglycemia? - Answer-After 4 hours
cortisol and growth hormone can be used to prevent prolonged hypoglycemia
Where do islets of langerhans get their blood supply and where do they get their
glucose from? - Answer-Blood from splenic, hepatic and superior mesenteric
arteries. Glucose uptake is facilitated by GLUT 2 transporters in canaliculi running
between cells.
What is glut2 and glut4? - Answer-They are glucose transporter proteins that move
glucose across cell membranes. Glut 4 requires insulin to activate it, but glut 2 does
