THE EFFECT OF NATURAL AND SYNTHETIC ESTROGENS ON RETICULOENDOTHELIAL SYSTEM FUNCTION

RECENT experiments in this laboratory(l);and by Halpern, Benacerraf, and Biozzi (2); Friedman and Byers et al. (3, 4, 5); Rice et al. (6); Brown et al. (7); and Lautsch (8) have indicated that the reticuloendothelial system (RES) plays an important role in cholesterol metabolism. In general, these data show that cholesterol-containing macromolecular aggregates ranging in size up to chylomicrons appear to be phagocytosed by RE cells. Blockade of the RES will cause a significant increase in the time that it normally takes for an induced hypercholesterolemia to disappear. On the other hand, stimulation of the RES (9) will accelerate the reduction of blood cholesterol levels. While work was being done on the role of the RES and cholesterol, other studies by Oliver and Boyd (10, 11, 12) and Barr et al. (13, 14, 15) were being carried out on the effect of certain estrogens in experimental and clinical atherosclerosis as well as xanthomatosis.