Gas turbine and method for operating a gas turbine

The gas turbine has turbine blades (12,14) in rows, each with an integrated cooling air channel. The blades forming the second row are positioned behind the blades in the first row, in flow direction of the working medium (M) and on the cooling air side, with an injection nozzle unit (48,70) for water between them. Both rows may be formed by guide blades connected to a turbine housing (6), or by rotor blades connected to a turbine shaft (8). Cooling air flowing out of the first blade row is cooled by injection of water, and then fed into the cooling channels in the second row.