Effects of Cortisol and 19-Nortestosterone1on the Free Amino Acid Pools and Amino Acid Uptake of Cultured Cells

Abstract

Three lines of cultured cells, HeLa, JTC-4 and L-929, were exposed to cortisol or 19-nortestosterone (at concentrations of 10 [mu]g/ml of medium), for 2 or 3 days. The amount per 108 cells, intracellular concentrations and the distribution ratio (ratio of intracellular concentration to that in the medium) of free amino acids of such cells were compared with those of control cells in each cell line. Cortisol affected HeLa cells so that the amount of amino acid per 108 cells was somewhat decreased with regard to aspartic acid and increased for threonine, serineandalanine; both the intracellular concentrations and the distribution ratios were markedly depressed for all the determined amino acids. JTC-4 and L cells had reduced amounts per 10^ cells and intracellular concentrations of all the amino acids as well as lower distribution ratios following cortisol treatment. 19-Nortestosterone, on the other hand, did not cause significant changes in the amount per 108 cells or intracellular concentrations of almost all the amino acids in HeLa and JTC-4 cells. HeLa cells were then studied with regard to the rate of uptake of glycine-l-c!4 from the medium by control and steroid-treated cells. Cortisol treatment decreased glycine uptake of the cells markedly at 10 and 30 min. of incubation, while 19-nortestosterone exerted no effect on uptake.