The present invention relates to a gas turbine, in particular an aircraft engine gas turbine having a shaft and a bladed turbine rotor joined therewith that has a first rotor segment which has a downstream rotating cascade of the turbine rotor and bounds a first space in the radial direction, this first space communicating with a first gas passage disposed in the shaft, and has a second rotor segment axially adjacent to the first rotor segment, which has at least one second rotating cascade of the turbine rotor and bounds in the radial direction a second space axially adjacent to the first space, this second space communicating with a second gas passage, wherein the first rotor segment has at least one first discharge opening for the discharge of gas from the first space upstream of the furthest downstream rotating cascade.