Studies in lipid histochemistry

Summary Conditions for a selective extraction of nonpolar lipids from tissue sections with acetone were investigated using methods of lipid chromatography, histochemistry and quantitative determination of lipid phosphorus.Extraction of nonpolar lipids is selective when water (present either in acetone or in tissue sections) is completely excluded from the extraction procedure and the extraction is carried out at 0–4° C for 20–30 minutes. Under these conditions a negligible amount of polar lipids is extracted which cannot be demonstrated histochemically. A very small amount of nonpolar lipids remaining in sections cannot be demonstrated histochemically either.A method for the preparation of anhydrous acetone was recommended and an extraction procedure devised. This is to be applied in cases where nonpolar and polar lipids are to be distinguished and as an integral part of all types of phospholipid stains.When water is present during the extraction procedure (either in acetone or in tissue sections) significant extraction of all polar lipids occurs which is proportional to the content of water, to the length of extraction and to the temperature. Under these conditions the extraction of nonpolar lipids is somewhat slower.The significance of selective extraction with anhydrous acetone in histochemical analysis of lipids is discussed particularly with reference to lipids in atherosclerotic plaques.