The Origins of Brown Adipose Tissue

Adipocytes that make up brown fat have two disparate lineages; one seems more closely related to muscle than to white adipose tissue. Adipocytes that make up brown fat have two disparate lineages; one seems more closely related to muscle than to white adipose tissue. What is the source of brown adipose tissue? During the formation of the three germ layers (gas trulation), the mesoderm fills the void between the outer shell (ectoderm) and the inner lining (endoderm). From this “filling” develop several specialized cell types, including myocytes, adipocytes, and chondrocytes. A close interrelationship among these cells can be seen when mesoderm-derived cell lines are treated with the modified nucleotide 5-azacytidine, which, when substituted for bona fide cytidine residues, results in demethylated DNA or, rather, in DNA that cannot be methylated. (Methylation of cytidine is commonly seen in regions of the genome that are transcriptionally . . .