AMP-activated protein kinase
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AMP-activated protein kinase or AMPK is an enzyme that is believed to have a role in regulating appetite and body weight. It is expressed in a number of tissues, including the brain, of mammals.
AMPK's primary known role is the monitoring of energy use within cells. Its activity is regulated by the hormone leptin. In the past, leptin has been linked to appetite suppression, although attempts to use it to control human obesity have been unsuccessful.
Recent research on mice at Harvard University, led by Barbara B. Kahn, has shown that when the activity of AMPK was inhibited, the mice ate less and lost weight. When AMPK levels were artificially raised the mice ate more and gained weight. Research in Britain has shown that the appetite-stimulating hormone ghrelin also affects AMPK levels.
A 2001 study (Zhou G et al) has indicated that the antidiabetic drug metformin (Glucophage®) acts by stimulating AMPK, leading to improved insulin resistance in the liver.
References
- Minokoshi Y, Alquier T, Furukawa N, Kim YB, Lee A, Xue B, Mu J, Foufelle F, Ferre P, Birnbaum MJ, Stuck BJ, Kahn BB. AMP-kinase regulates food intake by responding to hormonal and nutrient signals in the hypothalamus. Nature 2004;428:569-74. PMID 15058305.
- Zhou G, Myers R, Li Y, Chen Y, Shen X, Fenyk-Melody J, Wu M, Ventre J, Doebber T, Fujii N, Musi N, Hirshman MF, Goodyear LJ, Moller DE. Role of AMP-activated protein kinase in mechanism of metformin action. J Clin Invest 2001;108:1167–1174. DOI 10.1172/JCI200113505 (http://dx.doi.org/10.1172/JCI200113505).