Inhibition of RNA, DNA and protein synthesis by antisera in mouse lenkemic cells L5178YR
Abstract An in vitro system containing a rabbit serum mediumadapted subline of L5178Y cells and rabbit antiserum was used to study the effects of antibodies, in the absence of complement, on cells in culture. Heat-inactivated antiserurn inhibits cell growth and metabolism. These actions occur slowly. RNA synthesis is inhibited after 4 h, but the effects on the rates of protein and DNA synthesis become demonstrable only after 6 to 8, and 8 h, respectively. Maximal inhibition can be obtained after 24 to 48 h. These effects together with the apparent involvement of energy generating systems suggest that some indirect mechanism, triggered as a result of primary antigen-antibody reactions on the cell surface, is responsible.
Summary The influence on the blood cholesterol level and on cholesterol biosynthesis ([ 14 C] acetate incorporation) in the liver, small intestine and blood was investigated in rats after daily oral treatment with nicotinic acid, methyltestosterone and an anabolic steroid, PS-179, for one week. Plasma cholesterol levels were significantly decreased with PS-179, but not with nicotinic acid or methyltestosterone. None of the drugs altered the cholesterol levels in the liver and intestine. All drugs produced a significant decrease in the incorporation time of labelled cholesterol into liver and a significant increase in the intestine. Total cholesterol biosynthesis in liver and intestine were not altered with any of these drugs.