Role of Reticulo-Endothelial System in Blood Clearance of Cholesterol

¹ From the Clinique Médicale Propédeutique de l'Hopital Broussais, the Centre National de la Recherche Scientifique and the Centre de Recherches Allergiques de l'Association Claude Bernard, Paris, France

The clearance rate of colloidal carbon particles is only slightly impaired in rabbits rendered hypercholesteremic by overfeeding cholesterol. Rabbit serum cholesterol injected into rats is cleared by phagocytosis of the reticulo-endothelial cells whether the cholesterol is in the form of chylomicra (cloudy serum) or not (clear serum from fasting animals). The clearance of the foreign serum cholesterol from the blood follows an exponential function with respect to time as for many other colloids and the rate of clearance is inversely proportional to the quantity injected. Interference is observed between the clearance of cholesterol and other colloids when injected simultaneously. Pretreatment of rats with high doses of heparin increases substantially the speed of clearance of foreign serum cholesterol. The mechanism of the action of the R.E.S. in the metabolism of cholesterol is discussed.