CONTROL OF APETITE & METABOLISM
Glucose Homeostasis
NORMALSERUM
GLUCOSE80-120 mg/dl
NORMALSERUM
GLUCOSE80-120 mg/dl
SERUM GLUCOSESERUM
GLUCOSE
SERUM GLUCOSE
SERUM GLUCOSE
ISLET-CELLS
ISLET-CELLS
LIVER &MUSCLELIVER &MUSCLE
METABOLICDEMANDS
METABOLICDEMANDS
INSULININSULIN
GLUCOSE UPTAKEGLUCOSE UPTAKE
ISLET-CELLS
ISLET-CELLS
LIVER &MUSCLELIVER &MUSCLE
GLUCAGONGLUCAGON
GLYCOGENOLYSIS
GLUCONEOGENESIS
GLYCOGENOLYSIS
GLUCONEOGENESIS
CORTISONE & EPINEPHRINECORTISONE & EPINEPHRINE
MEALSMEALSGH
HYPOTHALAMUS: ARCUATE NUCLEUS
• ANTERIOR PITUITARY RELEASING HORMONES
• ENERGY RESERVES AND METABOLISM– OREXIGENIC/ANOREXIGENIC NEURONS– INCREASE/DECREASE METABOLISM– RECEPTORS FOR PERIPHERAL SIGNALS
ARCUATE NUCLEUS
• TWO TYPES OF NEURONS• MELANOCORTIN
– POMC– αMSH– INHIBITS FEEDING BEHAVIOR– INCREASES METABOLISM
• NEUROPEPTIDE-Y (NPY)– NPY– AGOUTI-RELATED PEPTIDE (AgRP)
• COMPETITIVE INHIBITOR OF MELANOCORTIN RECEPTORS
– STIMULATES FEEDING BEHAVIOR– DECREASES METABOLISM– INHIBITS MELANOCORTIN NEURONS
ARCUATE NUCLEUS
ARCUATE NUCLEUS
αMSH
METABOLIC RATE
FEEDING BEHAVIOR (-)
(+)
NPY
(+) (-)
(-)
ENERGY BALANCE INDICATORS
• LONG-TERM ENERGY STORES (ADIPOSE)– LEPTIN– INSULIN
• SHORT-TERM ENERGY STORES (SATIETY)– GHRELIN– PEPTIDE YY– CHOLECYSTOKININ (CCK)– GLP-1
Leptin
• Produced by fat cells– Level of leptin produced is directly
related to how much fat is in the fat cell.
• Peptide
• Anorexogenic
• Increases metabolism
Leptin Deficiency
ARCUATE NUCLEUS
ARCUATE NUCLEUS
αMSH
METABOLIC RATE
FEEDING BEHAVIOR (-)
(+)
NPY
(+) (-)
(-)
LEPTININSULIN
PEPTIDE YYCCK
GLP-1(?)
GHRELIN
CONTROL OF FOOD INTAKE AND METABOLISM
CCK