Composition of human adipose tissue from deep and subcutaneous sites.

I. Adipose tissue was obtained simultaneously from subcutaneous and deep sites in children undergoing elective surgery, and from different subcutaneous sites in adults. The lipid content and fatty acid composition were measured using gas-liquid chromatography and the number of cells counted after fixation in osmium tetroxide. The mean amount of lipid per cell was used as a measure of the size of the cells. 2. Cells from deep sites in children were significantly smaller (P < 0.001) than those from subcutaneous sites in the same individual. Cells from different subcutaneous sites were of similar size. 3. The fatty acid composition of the lipids was similar in tissue taken from the abdominal wall and from deep sites. 4. The fatty acid composition of adipose tissue from the lower leg showed an increase in the monounsaturated fatty acids and a decrease in the saturated fatty acids compared with the fatty acid composition of tissue from other subcutaneous sites.