Integration of Metabolism Flashcards
Glucose 6P acts as a metabolic junction point in what 4 pathways?
(1) Gluconeogenesis (RLE: Glucose 6 Phosphatase) -> Glucose
(2) Glycogenolysis (RLE: Glycogen Synthase) -> Glycogen
(3) Glycolysis (RLE: PFK1) -> Pyruvate
(4) PPP (RLE: Glucose 6P Dehydrogenase) -> Ribose 5P
Pyruvate acts as a metabolic junction point in what 4 pathways?
(1) Pyruvate Dehydrogenase -> ACoA
(2) Lactate Formation (RLE: Lactate Dehydrogenase) -> Lactate
(3) Nucleotide Metabolism (RLE: ALT) -> Alanine
(4) CAC via PDC -> OAA
ACoA acts as a metabolic junction point in what 3 pathways?
(1) CO2
(2) FA
(3) Ketone bodies
When are short term signals active?
During a meal
What is the function of long term signals?
Report overall energy status of body
i.e. Leptin secreted if not enough TAG stores
Where do these signals originate?
- GI tract
- Beta cells of pancreas (insulin)
- Adipocytes (leptin)
What is the primary target organ of the signals?
Brain - arcuate nucleus in hypothalamus
What are the two satiation signals?
- Glucagon like Peptide (GLP-1)
- CCK
Where are GLP-1 signals secreted from?
L cells in the intestine
Where are CCK signals secreted from?
Small intestine
What do both GLP-1 and CCK lead to increases in?
- increased insulin secretion
- increased insulin biosynthesis
- increased satiety
What do both GLP-1 and CCK lead to decreases in?
- decreased food intake
- decreased body weight
CCK
- short-term signal
- family of peptide hormones
- secreted into blood by cells in duodenum and jejunum regions of small intestine as a postprandial satiation signal
- binds to GCPR located in peripheral neurons
- leads to feeling of satiety
- also helps with digestion, stimulating secretion of pancreatic enzymes and bile salts from gallbladder
GLP-1
- short term signal
- hormone
- secreted by intestinal L cells
- binds to GPCR
- potentiates glucose-induced insulin secretion by beta cells of the pancreas
- inhibits glucagon secretion
Where is Ghrelin secreted from?
Stomach
Where does Ghrelin act?
Regions of the hypothalamus
What is the role of Ghrelin?
Stimulates apetite via GPCR on hypothalamus
Ghrelin secretion increases ___ a meal and ____ afterwards
- before
- decreases
What two key signal molecules regulate energy homeostasis over the time period of hours or days?
- Leptin
- Insulin
Leptin
- long term signal
- hormone
- secreted by adipocytes
- reports on status of TAG (decreases signal if high TAG stores)
Insulin
- long term signal
- secreted by beta cells of pancreas
- reports on status of blood glucose
Leptin makes tissues more sensitive to ___
Insulin
Increased adipose tissue means increased __ release
Leptin
Adipose tissue is considered what type of tissue?
Endorcine
What hormones does adipose tissue secrete?
- Adipokines (ex. leptin, adiponectin)
- RBP4 (retinol binding protein)
- resistin
What 3 effects does binding of Leptin to its receptors (located all over the body) and subsequent signaling result in?
(1) increase sensitivity of muscle and liver to insulin
(2) stimulates beta oxidation of FAs
(3) decreases TAG synthesis