Deuterated molecules in regions of high-mass star formation

We present the results of our studies of deuterated molecules (DCN, DNC, DCO${}^{+}$, N${}_2$D${}^{+}$ and NH${}_2$D) in regions of high-mass star formation, which include a survey of such regions with the 20-m Onsala radio telescope and mapping of several objects in various lines with the 30-m IRAM and 100-m MPIfR radio telescopes. The deuteration degree reaches $\sim$10${}^{-2}$ in these objects. We discuss its dependencies on the gas temperature and velocity dispersion, as well as spatial distributions of deuterated molecules. We show that the H${}^{13}$CN/HN${}^{13}$C intensity ratio may be a good indicator of the gas kinetic temperature and estimate densities of the investigated objects.