MadSci Network: Anatomy

Re: Re: Is Brown Fat Actually Different from White Fat?

Date: Sat May 5 19:52:18 2007
Posted By: Peter E. Hughes, Ph. D. Biochemistry,
Area of science: Anatomy
ID: 1177358141.An


The tissues are physiologically different in cellular structure and 
function. Mammals possess white, brown and yellow depot adipose tissue 
composed of adipocytes, fat cells.  

Most mammals have white adipose which serves as insulation and an energy 
depot.  White adipocytes have very thin ring of cytoplasm surrounding a 
single large lipid droplet and a single, flattened nucleus, there are very 
few discernable organelles.  The fat tissue is not profusely vascularized.

Brown adipocytes are polygonal in shape with a large volume of cytoplasm 
and contain multiple lipid droplets of much smaller size than the white 
adipocyte. There are mitochondria present, full of cytochromes, which 
gives them their color.  Their nuclei are round and usually centrally 
located.   The brown tissue is highly vascularized, plenty of capillaries 
to allow for rapid in and out of lipid to the peripheral blood supply.  
There are reports of melanin(brown) secretions being made also giving 
color to the adipose tissue.

While the fat droplet may be the same in each cell type, say, glyceryl 
tristearate… it may be mobilized and metabolized much faster by the 
organelles and vascularization of the brown adipose tissue.

Yellow adipocytes are actually white adipocytes in the animal consuming a 
diet high in carotenoids and xanthophylls.

The references have excellent photomicrographs of the two tissue types, 
they are unmistakable.

Thank you for your interesting question!  I hope this helps!
blobtype=html&artid=1202725, (Biochem J. 1964 March; 90(3): 518–521)
 http://physr (Physiol. Rev. 84: 
277-359, 2004; doi:10.1152/physrev.00015.2003)

The Linkage Relations of Yellow Fat in Rabbits, W. E. Castle,Proceedings 
of the National Academy of Sciences of the United States of America, Vol. 
19, No. 11 (Nov. 15, 1933), pp. 947-950

Current Queue | Current Queue for Anatomy | Anatomy archives

Try the links in the MadSci Library for more information on Anatomy.

MadSci Home | Information | Search | Random Knowledge Generator | MadSci Archives | Mad Library | MAD Labs | MAD FAQs | Ask a ? | Join Us! | Help Support MadSci

MadSci Network,
© 1995-2006. All rights reserved.