Identification of two cell types in rat brown fat by electron microscopy]

In the Rat brown adipose tissue, the authors have observed by electron microscopy two different cellular aspects : some cells are more dark, they contain numerous glycogen granules, their mitochondrias are pressed close together and the mitochondrial matrix is darker then the cristae ; in the light cells, the mitochondrias are more sparse and moderately electron dense. The two cellular aspects are also observed on thick sections.