Fig. 4.

Mitochondrial ultrastructure in hyperleptinemic white postadipocytes and in brown adipocytes. (A) Mitochondrial abundance in the cytoplasm of a postadipocyte. (B) Higher magnification of a hyperleptinemia-induced postadipocyte reveals that mitochondrial cristae are embedded in an electron-dense matrix. (C) Mitochondria from an untreated brown adipocyte. Although the magnification is lower than that in B, mitochondria appear much larger than those of white postadipocytes. In addition, their matrix is less electron-dense than in mitochondria of white postadipocytes, and their cristae traverse the entire width of the organelle.