177. Appetite Regulation

Question 1

__ levels have been shown to increase with weight loss, causing difficulty of maintaining weight loss

Also, amylin, CCK, and PYY levels have been shown to decrease with weight loss, thus satiety is more difficult to achieve

Answer 1

Ghrelin

Question 2

1. Inhibiting neurons that coexpress the orexigenic hormones NPY and AgRP
2. Stimulating neurons that coexpress the anorexigenic hormones alpha-MSH and CART

Answer 2

Leptin action in the arcuate nucleus

Question 3

Fasting plasma levels of __ are high in partients with anorexia nervosa and in subjects w/ diet-induced weight loss

Answer 3

Ghrelin

Question 4

Lesions to the __ hypothalamus induce excessive hunger

This area acts through MC4 receptor

Answer 4

Ventromedial

Question 5

What are times when fat stores need to be developed, thus when energy intake&raquo_space; energy expenditure?

Answer 5

Growth and development
Pregnancy
Recovery from an illness

Question 6

Peptide that is synthesized and released from endocrine L cells from the distal gut in response to food consumption
- particularly dietary fat

Levels increase w/in 30 minutes of nutrients reaching the distal gut

Answer 6

PYY

Question 7

One of the most potent orexigenic peptides peptides known

Hypothalamic __ mRNA levels are increased under conditions of acute food deprivation and chronic food restriction

Answer 7

NPY

Question 8

Neuropeptide that is abundantly present in the CNS

Provides a dominant inhibitory tone onto POMC

Answer 8

NPY

Question 9

Alpha-MSH’s receptor

When stimulated results in down-stream appetite control and energy balance

Answer 9

MC4R

Question 10

Hypothalamus responds with inflammation when pt is eating on a __

Inflammation may reduce responsiveness to normal neuropeptide signaling
- neuron damage

Causes a resistance to AgRP and POMC –> increase in body weight

Answer 10

High fat diet

Question 11

Is ideally suited as a receptor site for body adiposity as well as for integration of hormonal and neural signals because its “leaky BBB” and location at the base of the hypothalamus

Answer 11

Arcuate nucleus

Question 12

3% of subjects with severe early onset obesity have a __ mutation

Answer 12

Leptin receptor

Question 13

Breaks down GLP-1

Answer 13

DPP-4

Question 14

__ have been proven to have higher circulating leptin levels in proportion to fat mass when comparing them to their cohort

Answer 14

Females

Question 15

Released postprandially from I cells in the small intestine

Reduces food intake through CCK1 receptors on the vagus nerve

Answer 15

CCK

Question 16

For longer-term energy regulation, humoral signals derived from __ are integrated in specific regions of the hypothalamus

Answer 16

adipose tissue

Question 17

Refers to the energy expenditure associated with digestion, absorption, and increased sympathetic nervous system activity after eating a meal

5-10% of TEE

Answer 17

Thermic effect of feeding (TEF)

Question 18

Primary brain area regulating appetite and response to emotions

May mediate a hunger response even when an individual is not physically hunger

Answer 18

Amygdala

Question 19

Day-to-day intake is primarily governed by which hormone?

Answer 19

Ghrelin

Question 20

Leptin is a key regulator of signaling in the hypothalamic __ __

Answer 20

Arcuate nucleus (ARC)

Question 21

Only gut derived signal that increases hunger

Answer 21

Ghrelin

Question 22

Expressed in the CNS and in the distal ileum and colon
- rapidly released after food ingestion into the circulation in response to nutrient uptake

Incretin hormone - controls blood sugar by stimulating insulin secretion and inhibiting both glucagon secretion and gastric emptying

Answer 22

GLP-1

Question 23

2 neuropeptides that leptin acts to release from the arcuate nucleus
- anorexigenic

Answer 23

POMC (turns into alpha-MSH)

CART

Question 24

Mechanoreceptors and chemoreceptors in the GI tract signal through the __ to the brainstem for short-term regulation of appetite (hunger and satiety).

Answer 24

Vagal nerve

Question 25

Leptin system is more effective in signaling __ of energy stores and less effective in signaling energy surplus

Answer 25

Depletion

Question 26

Acts as an inverse agonist on constitutively active MC4 receptors During a negative energy balance, __ neurons are activated and act to suppress the MC receptor activity

Answer 26

AgRP

Question 27

__ is associated with metabolic regulation in gut hormones that are intended to drive energy stores back to initial replete levels

Answer 27

Weight loss

Question 28

Obesity is associated with __ As BMI increases, leptin increases - saturation occurs at a certain level

Answer 28

Leptin resistance

Question 29

The default in the brain is the __ system | - this is due to evolution's priority on eating to stay alive

Answer 29

Orixogenic (hunger)

Question 30

Peptide hormone released from the fundic region of the stomach Endogenous ligand for the growth hormone -secretagogue receptor (GHS-R) Only known factor to increase appetite Increased by fasting, fall after a meal

Answer 30

Ghrelin

Question 31

6% of children with severe obesity have a mutation in the __

Answer 31

MC4 receptor

Question 32

Lesions to the __ hypothalamus induce loss of appetite

Answer 32

Lateral

Question 33

__ administration has been shown to reduce food intake mediated through both peripheral and central mechanisms, via projection to the hypothalamus and brainstem areas Mimetic agents are used as drugs for Type 2 diabetes and cause weight loss

Answer 33

GLP-1

Question 34

Has a reproductive function by letting the brain known that menstruation can begin because body fat starts to accumulate during pregnancy

Answer 34

Leptin

Question 35

Result of a volitional mechanical work - exercise - daily activities Also, result of nonvolitional mechanical work - fidgeting - maintaining posture - spontaneous muscle contractions 15-30% of TEE

Answer 35

Physical activity

Question 36

Despite the elevated secretion and circulation of __ in obesity, CNS levels do not rise proportionately due to saturation of the leptin receptor and reduced intracellular signaling Thus, the CNS does not properly sense the expanded adipose mass

Answer 36

Leptin

Question 37

Refers to the energy expended for normal cellular and organ function during post-absorptive resting conditions Comprises 65% of TEE Can be clinically measured by indirect calorimetry

Answer 37

RMR (Resting metabolic rate)

Question 38

Pathways consist of dopaminergic neurons which originate in the ventral tegmental area and substantia nigra in the midbrain and project throughout the brain Responsible for "liking, wanting, and craving of food" - responsible for food-seeking behavior

Answer 38

Hedonic System (reward center)

Question 39

Receptors that mediate the effects of __ belong to the NPY receptor family with high affinity for the NPY2R in the arcuate nucleus

Answer 39

PYY

Question 40

Adipose-derived satiety hormone - secreted in diurnal rhythm Receptor in the CNS is a member of the IL-6 receptor family of type I cytokine receptors

Answer 40

Leptin

Question 41

Comprised of 3 components: 1. Resting metabolic rate (RMR) 2. Thermic effect of feeding (REF) 3. Energy expenditure of physical activity (PA)

Answer 41

Daily total energy expenditure (TEE)

Question 42

Neuroendocrine peptide that is co-secreted together w/ insulin from pancreatic islet beta-cells Plasma levels increase in response to nutritional stimuli Inhibits gastric emptying and glucagon secretion and reduces short-term food intake Directly stimulates neurons in the area postrema of the hindbrain Mimetic agents used as a DM medication and cause weight loss

Answer 42

Amylin

Question 43

Produced from the ob gene expressed in adipose cells Communicates the status of energy stores to the brain

Answer 43

Leptin

Question 44

2 neuropeptides that leptin acts to inhibit in the arcuate nucleus - orixogenic

Answer 44

AgRP and NPY

Question 45

Injury or lesions in the hypothalamus may result in a pattern of weight gain that is characterized as abrupt in onset and rapidly accelerating Causes include: - craniopharyngioma - head trauma - sarcoidosis - aneurysm - meningioma - metastasis - surgery - radiation

Answer 45

Hypothalamic obesity