Growth curves of Caco2 cells in arginine-free medium compared to arginine- and citrulline-supplemented medium.

Abstract

<p>Graphs are given for cells growing in complete medium (+Arg, rectangles), in medium without arginine (-Arg, circles) and arginine-free medium complemented with citrulline (+Citr, triangles). In A, cell numbers for proliferating Caco2 cells were measured by MTT assay; in B differentiated Caco2 cells were used. Samples were set up in triplicates, cell numbers expressed as relative to +Arg (d1). P-values calculated in comparison to complete medium values are shown for –Arg and for +Citr. After 3 d, growth was significantly reduced without arginine and citrulline could partially replace for the omitted arginine. In C, argininosuccinate synthase (ASS) mRNA expression in proliferating Caco2 cells at day 2 is displayed for the 3 different growth conditions, as assessed by qPCR in quadruplicates. Note the increase in ASS expression in the presence of citrulline.</p