Addendum to: Nature https://doi.org/10.1038/415339aPublished 17 January 2002

Nature is publishing an Editorial Expression of Concern on the article “Leptin stimulates fatty-acid oxidation by activating AMP-activated protein kinase”, by Minokoshi et al., to alert the readership that image integrity issues have been raised with some of the data.

Figure 2f: lanes 4 and 5 of the phospho-AMPK blot appear to be duplicated.

Figure 3b: lane 4 of the phospho-ACC blot is irregular.

Figure 3b: lanes 4 and 6 of the ACC-beta blot appear to be duplicated.

Figure 3c: lanes 1 and 4 of the phospho-AMPK blot appear to be duplicated.

The authors have provided original, contemporaneous data for all listed panels, obtaining identical results to the panels in the original study. Although we understand that the main results and conclusions have been shown to be reproducible in later studies by independent groups, it is the opinion of the editors that the above information should be taken into consideration when interpreting the data presented in this article.

Yasuhiko Minokoshi, Young-Bum Kim, Odile D. Peroni, David Carling and Barbara B. Kahn agree with the publication of this statement. Corinna Müller has not responded to correspondence about this statement. Lee Fryer is deceased.