NewPathway

Leptin: A New Pathway for a Familiar Hormone

Figure 1: Leptin binds to its receptors in the hypothalamus and causes a cascade of events. Click here or on the figure above to learn more! Figure 2: Evidenced in the paper by Minokoshi and Kim, Leptin can also increase the activity of AMPK after injection directly in the muscle.	Leptin Activates AMP-activated protein kinase by phosphorylating it. This process can occur directly after leptin is injected into skeletal muscle ("early activation") or after leptin has traveled to the hypothalamus ("late activation").
Figure 3: Phosphorylated AMPK inactivates ACC which in turn decreasesthe production of Malonyl CoA. Click here or on the figure above to learn more!	AMP-activated protein kinase is the key mediator of this pathway. In turn, AMPK phosphorylates Acetyl CoA Carboxylase, thus inhibiting its function. This results in reduced production of Malonyl CoA.
Figure 4: Leptin indirectly decreases the amounts of Malonyl CoAin the cytoplasm and thus allows more fatty acids to enter the Mitochondria for oxidation. Click here, or on the figure above to learn more!	Malonyl CoA is a potent inhibitor of fatty acid oxidation. Thus, the levels of fatty acid oxidation are increased.
Figure 5: Clusters of fat inside of thigh muscle. Click here or on the figure above for more information!	What Are the Implications of the New Pathway?
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