Serum lipoproteins control cell cholesterol content by regulating its uptake. biosynthesis. and excretion. Monolayers of cultured fibroblasts were used to study interactions with human high density (HDL) and low density (LDL) lipoproteins doubly labeled with [(3)H]cholesterol and (125)I in the apoprotein moiety. https://foldlyers.shop/product-category/headers-idc/