Hydrocortisone enhancement of insulin's action on macromolecular synthesis in MCF-7 cells.

In MCF-7 human breast cancer cells, insulin stimulated the rate of [3H]uridine incorporation into RNA, [3H]thymidine incorporation into DNA, and [3H]leucine incorporation into protein. In addition, hydrocortisone appeared to augment the effect of insulin, by further increasing the rate of [3H]uridine incorporation into RNA and [3H]thymidine incorporation into DNA. A significant increase in the total amount of DNA and protein was present in cultures treated with insulin compared to untreated controls. Hydrocortisone was shown to augment the insulin effect on total protein accumulation and total RNA accumulation in MCF-7 cells.