Isotope effect of ¹³C‑enriched testosterone on human cells

The present study investigated the carbon isotope effect of carbon‑13 (13C)‑enriched testosterone on human cells; studies on the carbon isotope effects of a bioactive compound are limited. For this purpose, human osteoblasts, aortic endothelial cells and umbilical vein endothelial cells were treated with testosterone and 13C‑enriched testosterone. The cell growth rates and bioactivities of osteoblasts were measured. At physiological concentrations, testosterone promoted cell proliferation, whereas 13C‑enriched testosterone exerted a neutral and concentration‑independent effect on the cells. On the whole, the findings of the present study demonstrated that 13C‑enriched testosterone exerted a significant isotope effect on human cells; this needs to be taken into account in stable isotope‑based biology research.