As an attempt to find suitable materials for spintronic devices we have investigated the electronic structure and magnetic properties of rare-earth compound GdN as a function of unit cell volume. Based on a first-principles calculation we observe that there is a transformation in the conduction properties associated with the volume increase, first from half-metallic to semimetallic, then ultimately to semiconducting. We show that applying stress can alter the carrier concentration as well as mobility of the holes and electrons in the majority spin channel. In addition, we find that the exchange parameters depend strongly on lattice constant, thus the Curie temperature of this system can be enhanced by applying stress or doping impurities. This demonstrates that GdN is a potentially excellent spintronic material.