Metabolism

Question 1

FASTED STATE

Answer 1

Energy intake > energy expenditure
Glucose production > glucose uptake

• increase in food intake
• inability of body to undergo phenomenon of WAT browning (adipocytes favour energy storage state)
• allows for production of glucose from liver.
• Secretion of Ghrelin from ghrelinergic cells in stomach
• Ghrelin high in blood
• BBB is open
• GR enters and interacts with GR receptors on AgRP neurons
• this induces hunger and food seeking behaviour
• AgRP neurons use neuropeptide AgRP which is an ANTAGONIST at the MC4R receptor on second order neurons of VMH, PVH & LH.

PVH = controls coordination of WAT Browning.
LH & VMH key roles in feeding behaviour.

Question 2

FED STATE

Answer 2

Energy expenditure > energy intake
Glucose uptake > glucose production

• decrease in food intake
• allows for promotion of WAT browning (formation of beige adipocytes within adipose tissue). Allows for energy expenditure to occur.
• shuts off hepatic glucose production (stopping an excessive amount of glucose from entering the blood)
• insulin secreted from pancreas
• leptin sets gain of system
• BBB somewhat closed (affects ghrelin more than leptin/insulin)
• leptin and insulin interact with receptors on POMC and AgRP neurons.
• leptin and insulin INHIBIT AgRP neurons
• leptin and insulin ACTIVATE POMC neurons
• result in production of alpha-MSH (AGONIST at MC4R receptor on neurons of PVH & LH).