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