22: Metabolic Integration Flashcards
Define: the fed state, the basal state, & the starved state.
Fed = following meal
Basal = after an overnight fast
Starved = several days or more of deprivation
Glycogen stores ______, fat stores _____, & protein stores ________.
Glycogen stores glucose, fat stores ATP, & protein stores ATP & glucose.
ATP is an immediate energy source. Glucose cannot be made from fat.
Synthesis & degradation ___ occur simultaneously. If this occurs, this is called a futile cycle.
Synthesis & degradation do not occur simultaneously. If this occurs, this is called a futile cycle.
The only futile cycle that exists is that when lypolysis is occuring, some FFA are being re-esterified to tryglycerol. This is s control mechanism on the rate of lypolysis.
Glucogenic amino acids can be converted to _______ & ketogenic amino acids can be converted to ______. Leucine and Lysine are the only _______ and all the Ts [tryptophan, tyrosin, threonine] + Phenylalanine & Isoleucine are_______ while all others are ______ only.
Glucogenic amino acids can be converted to glucose & ketogenic amino acids can be converted to ketones (by first making them acetyl coA = this is why you cannot make glucose from fatty acids). Leucine and Lysine are the only ketogenic and all the Ts [tryptophan, tyrosin, threonine] + Phenylalanine & Isoleucine are ketogenic and glugogenic while all others are glucogenic only.
The intermediates of the TCA cycle are constantly leaking out to other metabolic pathways. Citrate goes to _______, a-ketoglutarate becomes ______ & goes to _____, succinyl coA goes to ____, malate goes to ______, OAA goes to ______.
The intermediates of the TCA cycle are constantly leaking out to other metabolic pathways. Citrate goes to fatty acid synthesis, a-ketoglutarate becomes neurotransmitter & goes to amino acid synthesis, succinyl coA goes to heme synthesis, malate goes to gluconeogenisis, OAA goes to amino acid synthesis.
Catabolic enzymes are active when ______. Anabolic enzymes are inactive when _______. Glycogen phosphorylase, phosphorylase kinase, & hormone sensitive lipase are _____ enzymes. Acetyl coA carboxylase, glycogen synthase, & HMG coA reductase are _____ enzymes.
Catabolic enzymes are active when phosphorylated. Anabolic enzymes are inactive when phosphorylated (active when deophosphorylated). Glycogen phosphorylase, phosphorylase kinase, & hormone sensitive lipase are catabolic enzymes. Acetyl coA carboxylase, glycogen synthase, & HMG coA reductase are anabolic enzymes.
Insulin is an anabolic hormone which promotes _______. Glucagon is a catabolic hormone which promotes _______ of cAMP & PKA. Epinephrine is used for signaling immediate energy needs so it is _______.
Insulin is an anabolic hormone which promotes dephosphorylation. Glucagon is a catabolic hormone which promotes phosphorylation of cAMP & PKA. Epinephrine is used for signaling immediate energy needs so it is catabolic.
Glycolysis is is ______. After the max amount of glycogen synthesis, the insulin is high & glucose is made into pyruvate. Then it goes through TCA & becomes _____ & becomes fatty acid.
Glycolysis is is anabolic. After the max amount of glycogen synthesis, the insulin is high & glucose is made into pyruvate. Then it goes through TCA & becomes citrate & becomes fatty acid.
Caloric Content of Dietary Components in kcal/g: Carbohydrate __, Protein __, Fat __, Alcohol __
Caloric Content of Dietary Components in kcal/g: Carbohydrate 4, Protein 4, Fat 9, Alcohol 7
Objective 1: Understand the major organ-specific changes in these pathways in different metabolic states: fed, basal (overnight fasting), prolonged starvation, and uncontrolled Type 1 diabetes.
Objective 2: Learn how major metabolic pathways for fats, carbohydrates and amino acids interconnect in the liver and in other major organs (muscle, adipose tissue, brain, red blood cells).
Objective 3: Understand the roles of insulin and of counterregulatory hormones (glucagon, epinephrine, cortisol) in regulating these changes.
See figures in pgs. 421, 423, 425, 426, 429, 430, 431, 434-436,
Contrast starvation & untreated type 1 diabetes.
The main difference between these two states is insulin.
Starvation:
- Low insulin/glucagon ratio, but some insulin always present
- Moderately high rate of lipolysis in fat cells
- Moderate production of KB by liver
- Metabolic adjustments are gradual and manageable. Gradual shift in use of KB as fuel by various extrahepatic tissues (e.g., induction of needed brain enzymes). Any excess KB in blood can be excreted by kidneys.
- No ketoacidosis
Diabetes:
- Zero circulating insulin
- Uninhibited, maximal (‘runaway’)
lipolysis in fat cells
- Maximal production of KB by liver. Increased KB in blood, causing metabolic acidosis = ketoacidosis.
- KB production overwhelms KB removal. There is metabolism in extrahepatic tissues, excretion by kidneys, & exhalation of acetone.
