THE AIM OF THE PRESENT WORK IS TO ISOLATE THE TWO KINDS OF LIVER CELLS (HEPATOCYTES) BY A SIMPLE, EASY AND ACCURATE TECHNIQUE USING A GRADIENT SOLUTION OF PERCOLL. TWO LAYERS OF HEPATOCYTES ARE SEPARATED ACCORDING TO ITS DENSITY. THE UPPER LAYER IS THE LOWER DENSITY LAYER WHICH INCLUDED THE PERICENTRAL HEPATOCYTES, WHILE THE LOWER LAYER IS THE HIGHER DENSITY AND REPRESENTED THE PERIPORTAL HEPATOCYTES. THE SEPARATION METHOD DEPENDS ON THE IDENTITY OF HEPATOCYTES DENSITY TO THE DENSITY OF THE PERCOLL LAYER, THE SEPARATION IN ONLY TWO LAYERS FACILITATE THE COLLECTION OF EACH TYPE OF CELLS ALONE WITHOUT ANY CONTAMINATION WITH THE OTHER KIND OF HEPATOCYTES. THE RESULTS WERE CONFIRMED BY DIFFERENT BIOCHEMICAL DETERMINATION EITHER IN VIVO AND IN VITRO STUDIES BY USING TOXIC COMPOUNDS WHICH SELECTIVELY DAMAGE ONE KIND OF HEPATOCYTES AND NOT THE OTHER ONE TO BE SURE THAT THE SEPARATED LAYER CONTAIN ONE DEFINITE KIND OF HEPATOCYTES BUT NOT THE OTHER TYPE, HENCE WE DO NOT NEED TO CONFIRM THE RESULTS BY ELECTRON MICROSCOPE. WE STUDY THE HEPATOCYTES VIABILITY TO BE SURE THAT THE SEPARATION TECHNIQUES NOT AFFECT THE CELLS VIABILITY. THEREFORE, THIS TECHNIQUE TENDS TO BE AN ACCURATE METHOD FOR BIOCHEMICAL DETERMINATIONS ON LIVER CELLS ESPECIALLY IN CYTOTOXIC STUDIES
