Characteristics of the insulin stimulation of DNA, RNA and protein metabolism in cultured human mammary carcinoma cells.

In a mammary gland cell line (MCF-7) of human origin, insulin stimulated the rates of RNA, DNA and protein biosynthesis. These effects were observed with concentrations of insulin ranging from 10(-6) M to 10(-10) M. Enhanced rates of [3H]leucine incorporation into protein and [3H]uridine incorporation into RNA were observed within 1 h after exposing the cells to insulin. In contrast, a stimulatory effect of insulin on the rate of [3H]thymidine incorporation into DNA was only detectable following a 12--16 h incubation with insulin. Insulin also enhanced the rate of uptake of [3H]leucine, [3H]uridine, and [3H]thymidine into the MCF-7 cells. Finally, incubation with insulin increased the total amount of DNA, RNA and protein in these cells.