Fibroblasts as an Experimental Tool in Metabolic and Hormone Studies

Abstract. .Before cell cultures can be used as a tool for metabolic and endocrine research, standardized conditions for stationary and growing cells must be established. Our results with chicken embryo fibroblasts and with WI‐38 human fibroblasts demonstrate that the metabolic behaviour of these cells differs depending on whether they are in a stationary phase (without serum) or in a growing phase (with serum). Energy during growth is derived almost exclusively from glycolysis. Two additional factors determine the rate of glucose consumption and lactate production: The glucose concentration in the medium and the density of the cells, i.e. the number of cells per surface area. Using a pulse of labelled thymidine it can be shown that after a delay fibroblasts simultaneously go through the first S‐phase under the stimulatory influence of serum. Stationary cells behave metabolically as contact‐inhibited cells with regard to glucose consumption and lactate production. It appeals that serum triggers off a sequence of metabolic events including increased glycolysis, thymidine incorporation into DNA and growth.