Fat Flashcards
What are the products of fat oxidation?
CO2 + H2O + ATP
What type of fat is responsible for heat generation?
brown fat
BMI calculation?
BMI = weight (lbs) x 703 / height (inches)
T or F: BMI increases w/ age?
TRUE
BMI > 30 is considered?
Obese
BMI 25-29.5 is considered?
Overweight
BMI 18.5-24.9 is considered
healthy lean
BMI < 18.5 is considered?
Underweight
Dyslipidemia/hypderlipidemia can lead to what BMI classification?
Obese
What are the 3 types of adipocytes?
White, brown, beige
What are the 2 fat depots?
WAT BAT
BAT is greatest in what age range?
Infancy Decreases w/ age
Cold temperatures stimulate TSH to release T3/4 or epinephrine to produce heat?
Cold → TSH → T4/3 → UCP1 (uncoupling protein-1) → mitochondria → + FA = heat production
How does stress lead to heat production?
Stress → Epinephrine → G-protein 2nd msgr → TG breakdown to FA → mitochondria → + UCP1 = heat production
Does TSH & T3/T4 or Epinephrine allow for the direct transfer of food energy into heat energy?
TSH & T3/T4
T3, Epi, cold, hepativ bile acids, ANP, BNP and irisin (skeletal muscle hormone) stimulates what adipocyte?
Beige
What hormone promotes fuel storage and stimulates antilipolytics effect? ↑ LPL → converts TG to FA ↑ GLUT 4 → ↑ glucose uptake in adipocytes Inhibits hormone sensitive lipase (HSL)
Insulin
What hormones stimulate the lipolytic effect? (4)
- Epi (via HSL and adipose tissue triglyceride lipase (ATGL)) 2. Cortisol 3. Glucagon 4. GH
What hormone does not regulate fuel metabolites due to slow onset to adjust blood levels of nutrients?
Thyroid hormone
Does the subQ depot or visceral depot provide FA for energey during exercise?
subQ depot
Do women have higher subQ depots or visceral depots?
subQ due to higher whole body insulin sensitivity (gynecoid adiposity)
Do women have higher or lower whole body sensitivity to insulin?
Higher (gynecoid adiposity)
Do men have higher subQ depots or visceral depots?
Visceral (omental and mesenteric)
In the visceral depot, blood drain via what to clear FA by the liver?
Hepatic portal
Do men have higher or lower sensitivity anti-lipolytic effects of insulin?
Lower (android adiposity)
What hormone leads to android adiposity in men?
Testosterone
Is hypertrophy of adipocytes reversible?
Yes
Is hyperplasia ( ↑ # adipocytes) of adipocytes reversible?
No
TNFa & Interleukin 6 have what effect on inflammation?
proinflammatory adipokines
What pro-inflammatory adipokine regulates cytokines that promote tumor growth?
Interleukin 1
Hypertrophy of adipocytes → Diffusion limited hypoxia → necrotic conditions → ↑ macrophages. M1 macrophages → pro-inflammatory cytokines (tumor necrosis factor a) → inhibits insulin action What does this pathway result in?
Insulin resistance, low grade inflammation → ↑ ROS, ↑ CA risk
What are the 2 hormones of the adipose organ (adipokine)?
Leptin Adiponectin
What adipokine regulates metabolism and provides feedback signal on appetite?
Leptin
What adipokine is insulin sensitizing and anti-inflammatory?
Adiponectin
Resistin, a hormone of glucose metabolism, ↑ LDL and is associated with what form of DM?
T2DM
What hormone of glucose metabolism has a role body metabolism, insulin sensitivity and is anti-inflammatory, anti-atherosclerotic, and CV protective?
Omentin
What hormone of glucose metabolism is released from visceral fat and binds insulin receptor → hypoglycemic effect?
Visfatin
Significant and rapid weight loss will have what effect on leptin levels?
Reduced leptin levels (not fully recoverable, low levels of leptin regained = weight regained)
In healthy condition, leptin will inhibit the secretion of what?
Insulin (via negative feedback)
Negative feedback from leptin on insulin produces what effect on glucose?
Gluconeogenesis by agal stimulation, muscle, heart, BAT glucose uptake (via ANS- sympathetic NA)
What happens if negative feedback by leptin on insulin is lost? (4)
- hyperinsulinemia 2. ↑ weight gain 3. aggravates DM 4. ↑ leptin (which increases appetite)
What are the 3 primary beneficial affects of adiponectin?
- Increased insulin sensitivity
- Anti-inflammatory
- Anti-atherogenic
What tissue releases adiponectin?
WAT (low levels w obesity)
What effect does adiponectin have on CV tissue?
Cardioprotective in heart/ endothelium, decreases BP
What effect does adiponectin have on skeletal muscle?
Increases GLUT4
What effect does adiponectin have on the liver?
Increased glucose uptake and energy storage
Adiponectin acts as an autocrine signal in adipose tissue to exert what effects?
Promotes adipogenesis and insulin-directed glucose transport
Leptin signaling in the arcuate nucleus (ARC) results in release of neuropeptides that exert control of what?
Appetite
Ghrelin released from the stomach peaks before food and falls after meals to increase and decrease what hormones?
Increase NYP (neuropeptide Y)
Decrease leptin and POMC (melanocortins)
With respect to leptin signaling, what proteins act to suppress appetite? (anorexigenic)
Melanocortins (POMC)
(leptin also anorexigenic)
With respect to leptin signaling, what proteins act to stimulate? (orexigenic)
Neuropeptide Y (NPY) and agouti-related protein (AgRP)
(these proteins also decrease BMR and fertility)
What anorexigenic POMC is secreted from adipose tissue, is essential for body weight regulation, and shows reduced levels with weight loss?
Leptin
What anorexigenic POMC acts to inhibit NYP cells?
Insulin
What anorexigenic POMC acts by slowing gastric emptying resulting in satiety?
Amylin
What anorexigenic POMC is produced in the intestines and acts to inhibit NPY neurons?
Peptide PTT
What anorexigenic POMC is released from the mucosal lining of the small intestine and acts to signal satiety in response to a meal?
Cholcystokinin (CCK)
With respect to anorexigenic inputs, a decrease in CRF inhibits what?
HPA axis