Deck 44: Gut-Brain Interactions and Feeding Behaviors

Question 1

You are performing laser ablation experiments on laboratory animals to ascertain the effects, on feeding behaviors, of damage to certain regions of the brain. In one series of experiments it is found that loss of the targeted brain region causes the animals eat nearly continuously, no matter the time of day, nor the composition of the chow. The ablation was centered on the hypothalamus and these results strongly indicate the damage affected which of the following regions of this structure?

A) lateral hypothalamic area (LHA)
B) nucleus of the solitary tract (NTS, NST)
C) paraventricular nucleus of the hypothalamus (PVN, PVH)
D) suprachiasmatic nucleus (SCN)
E) ventromedial hypothalamus (VMH, VMN)

Answer 1

ventromedial hypothalamus (VMH, VMN)

Question 2

You are assessing the effects of injecting synthetic peptides into laboratory mice. You discover that injecting one of the peptides induces hyperphagia. Which of the following hormones is most likely being mimicked by the actions of the synthetic peptide?

A) cholecystokinin, CCK
B) cocaine- and amphetamine-regulated transcript, CART
C) ghrelin
D) α-melanocyte stimulating hormone, α-MSH
E) peptide tyrosine tyrosine, PYY

Answer 2

ghrelin

Question 3

Fatty acid metabolism within the brain is not a significant pathway for the generation of ATP. However, this does not mean that fatty acid metabolism is not a useful pathway in brain. Which of the following would be expected to be found at elevated levels in brain tissues following the metabolism of free fatty acids?

A) acetate
B) alanine
C) ceramide
D) citrate
E) sphingosine

Answer 3

ceramide

Question 4

You are examining feeding behavior in laboratory animals in response to the addition of a test organic molecule to their chow. Following consumption of the compound you discover that the animals loose interest in food. Additional experiments demonstrate that central metabolism of palmitic acid is reduced in these animals. Given these observations you believe that the test compound is most likely inhibiting which of the following hypothalamic enzymes?

A) acetyl-CoA carboxylase
B) carnitine palmitoyltransferase I
C) fatty acid synthase
D) malonyl-CoA decarboxylase
E) medium-chain acyl-CoA dehydrogenase

Question 5

You are testing the effects of central administration of inhibitors of fatty acid oxidation on hypothalamic activity. Which of the following neuropeptides would you expect to see expressed at elevated levels in response to the actions of the inhibitor?

A) agouti-related peptide, AgRP
B) cocaine- and amphetamine-regulated transcript, CART
C) galanin
D) melanin-concentrating hormone, MCH
E) neuropeptide Y, NPY

Question 6

The pancreatic polypeptide (PP) family of proteins binds to a family of receptors that were originally characterized as NPY receptors. There are 4 NPY receptors in humans and they are designated as Y1, Y2, Y4, and Y5. Which of the following hormone-receptor combinations is involved in exerting anorexigenic responses?

A) NPY + Y1
B) NPY + Y4
C) PP + Y4
D) PYY + Y2
E) PYY + Y4

Question 7

Which of the following gut hormones is known to bind to one of the cholecystokinin receptors resulting in activation of the oxyntic glands of the
Stomach?

A) cholecystokinin, CCK
B) gastrin
C) ghrelin
D) GLP-I
E) protein tyrosine tyrosine, PYY

Question 8

Laser ablation experiments are being performed in laboratory animals to ascertain the effects, on feeding behaviors, of damage to certain regions of the brain. In one series of experiments it is found that loss of the targeted brain region causes the animals to avoid food, no matter the time of day, nor how long they have gone without eating. The ablation was centered on the hypothalamus and these results strongly indicate the damage affected in which of the following regions of this structure?

A) lateral hypothalamic area (LHA)
B) nucleus of the solitary tract (NTS, NST)
C) paraventricular nucleus of the hypothalamus (PVN, PVH)
D) suprachiasmatic nucleus (SCN)
E) ventromedial hypothalamus (VMH, VMN)

Question 9

A patient is diagnosed with problems in emptying the gallbladder. On a blood checkup, one hormone/peptide that is known to stimulate gallbladder contraction is inappropriately low. Which of the following hormones is most likely deficient leading to the observed symptoms?

A) cholecystokinin, CCK
B) gastrin
C) GLP-1
D) pancreatic polypeptide
E) peptide tyrosine tyrosine, PYY

Question 10

Blocking the actions of which of the following hormones would be expected to lead to the greatest level of appetite suppression?

A) adiponectin
B) ghrelin
C) GLP-1
D) obestatin
E) peptide tyrosine tyrosine, PYY

Question 11

Several gut-derived factors control feeding behaviors elicited by the brain. Most of these factors exert their effects by reducing the desire for food intake. The synthesis of one of these factors is stimulated by fat intake and inhibited by leptin release from adipose tissue. In addition, vagal efferents are not required for release but the activity of another gut factor is involved in its release. Which one of the following factors fits each of these statements?

A) apolipoprotein A-IV, apoA-IV
B) cholecystokinin, CCK
C) ghrelin
D) GLP-1
E) peptide tyrosine tyrosine, PYY

Question 12

The gut peptide ghrelin is posttranslationally modified before it is fully active. Which of the following represents the type of modification that is necessary for its biological action?

A) acetylation
B) acylation
C) methylation
D) phosphorylation
E) prenylation

Question 13

You are investigating the potential of a new drug to be useful in treating obesity. Specifically you are hoping that the drug either stimulates anorexigenic peptide release or inhibits orexigenic peptide release. You discover that addition of the drug to water consumed by your test animals results in inhibition of glucose oxidation within the hypothalamus. Based upon your findings what peptide would you most likely expect to see increased in these test animals?

A) agouti-related peptide, AgRP
B) cocaine- and amphetamine-regulated transcript, CART
C) galanin
D) melanin-concentrating hormone, MCH
E) neuropeptide Y, NPY

Question 14

A defect in activity of which of the following hormones has been associated with the sleep disorder known as narcolepsy?

A) agouti-related peptide, AgRP
B) cocaine- and amphetamine-regulated transcript, CART
C) galanin-like peptide, GALP
D) melanin-concentrating hormone, MCH
E) orexin A

Question 15

Vagal afferents are involved in the responses of the CNS to certain gastrointestinal hormones. Which of the following gut hormones exerts some of its orexigenic responses via these vagal pathways?

A) cholecystokinin, CCK
B) ghrelin
C) glucose-dependent insulinotropic peptide, GIP
D) GLP-1
E) protein tyrosine tyrosine, PYY

Question 16

Which of the following gut hormones is responsible for the feeding phenomenon referred to as the ileal brake?

A) CCK
B) ghrelin
C) GIP
D) oxyntomodulin, OXM
E) protein tyrosine tyrosine, PYY

Question 17

Although the level of leptin secretion is proportional to the amount of fat in adipose tissue, obese individuals are resistant to the anorexigenic effects of the increased hormone levels. Which of the following hypothalamic hormones would be expected to have the greatest increase in expression as a consequence of obesity-induced leptin resistance?

A) cocaine- and amphetamine-regulated transcript, CART
B) galanin-like peptide, GALP
C) α-melanocyte stimulating hormone, α-MSH
D) neuropeptide Y, NPY

Question 18

You are studying a strain of laboratory mice that get obese even on a low-fat lab chow. In examination of the brains of these mice you find an abnormal poorly developed area of the hypothalamus. A defect in which of the following regions would most likely account for the observed obesity?

A) lateral hypothalamic area (LHA)
B) nucleus of the solitary tract (NTS, NST)
C) paraventricular nucleus of the hypothalamus (PVN, PVH)
D) suprachiasmatic nucleus (SCN)
E) ventromedial hypothalamus (VMH, VMN)

Question 19

Which of the following brain regions sends and receives information to the visceral organs via the vagal nerve?

A) arcuate nucleus (ARC)
B) area postrema
C) nucleus of the solitary tract (NTS, NST)
D) perifornical lateral hypothalamus (PFLH)
E) ventromedial hypothalamus (VMH)

Question 20

Which of the following hormones is expressed and released from the stomach and is involved in the stimulation of food intake?

A) cholecystokinin, CCK
B) ghrelin
C) GLP-1
D) neuropeptide Y, NPY
E) protein tyrosine tyrosine, PYY

Question 21

Which of the following correctly reflects the consequence of insulin binding its receptor in the hypothalamus?

A) activation of melanin-concentrating hormone (MCH) release
B) activation of α-melanocyte stimulating hormone (α-MSH) release
C) activation of neuropeptide Y (NPY) release
D) inhibition of cocaine- and amphetamine-regulated transcript (CART) release
E) inhibition of galanin release

Question 22

Genome-wide screens for gene polymorphisms associated with a predisposition to obesity have identified several loci. Which of the following hormone genes could be expected to most likely lead to an increased propensity for obesity if it were defective?

A) Agouti-related peptide, AgRP
B) cocaine- and amphetamine-regulated transcript, CART
C) neuropeptide Y, NPY
D) oxyntomodulin, OXM
E) peptide tyrosine tyrosine, PYY

Question 23

Agouti-related peptide (AgRP) is an orexigenic hormone that functions to increase the desire for food intake by antagonizing the actions of which of the following anorexigenic hormones?

A) cocaine- and amphetamine-regulated transcript, CART
B) galanin-like peptide (GALP)
C) GLP-1
D) α-melanocyte stimulating hormone, α-MSH
E) peptide tyrosine tyrosine, PYY

Question 24

Patients with functional dyspepsia (disturbed indigestion) and prominent nausea frequently experience spurts of excessive acid exposure to the upper duodenum. This results in pancreatic secretion, mainly through the action of which of the following substances?

A) cholecystokinin
B) gastrin
C) glucagon
D) secretin
E) vasoactive intestinal polypeptide

Question 25

A 30-year-old man seeks help because he lost weight and feels full after eating only a small amount of food. He is diagnosed with a delay in gastric emptying. Which of the following hormones has at physiological levels the strongest effect in inhibiting gastric emptying?

A) cholecystokinin
B) gastrin
C) glucose-dependent insulinotropic peptide
D) motilin
E) pancreatic polypeptide

Question 26

A 60-year-old woman is admitted to the hospital with a fever and severe diarrhea for the last 24 hours. Cultures of blood, cerebrospinal fluid, urine, and stool are all negative for pathogens. The profile of gut hormones reveals elevated levels of vasoactive intestinal polypeptide (VIP). An analogue of which of the following would most likely lower her VIP levels?

A) erythromycin
B) histamine
C) motilin
D) somatostatin
E) trypsin