A METHOD FOR THE DETERMINATION OF TOTAL LIPIDES AND WATER IN BRAIN TISSUE

Abstract

Although many methods have been used for the determination of total lipides, few have been described with detailed directions for application to animal tissues, and there is none, as far as the author is aware, which is applicable to brain tissue, which permits the determination of water and lipides in the same sample of tissue, and which satisfies all of the following criteria. (a) The tissue should be so thoroughly fragmented that the sampling error in taking aliquots is negligible. This is particularly important in the analysis of brain because of the wide variation in lipide composition among the different structures of that organ. (b) Evaporation of water should be avoided during the fragmentation of the tissue and weighing of the samples. Neglect of this precaution may introduce considerable error. (c) Extraction of the lipides should be complete. (d) Non-lipide impurities should be removed from the extracts before the lipides are measured. (e) To avoid degradation of the lipides, undue exposure to air and high temperature should be avoided. (f) The procedure should be as simple as possible, and should be reasonably accurate. In addition, the determination of water in the tissue is required in many investigations so that lipide data may be related to dry weight; to conserve tissue, it is desirable that this analysis be carried out on the same sample in which the lipides are measured. A method which satisfies these criteria is described in this communication. The method was designed for analysis of the brain, but since brain lipides are more complex and difficult to extract than those of any other tissue, it should be readily applicable to any tissue which can be disintegrated under the conditions described in step (a) of the procedure. Several of the techniques, described in other steps, are generally applicable in lipide analysis.