Thermospheric densities of atomic and molecular nitrogen were measured from February 1976 through December 1978 by the open source neutral mass spectrometer on the equatorial Atmosphere Explorer E satellite. During this period a significant increase in N densities was observed at altitudes of 250 km and above. We believe the increases can be explained by increased production of N due to enchanced solar extreme ultraviolet radiation but not by a simple rise in thermospheric temperature. Empirical modeling of N densities at 250 and 375 km by using stepwise regression techniques indicates that the increased solar EUV fluxes in the 800--1000 ¿ range are sufficient to account for the observed rise in N densities at 250 km from June 1976 to June1977 and are the dominant factor in the density increase of a factor of 5 observed at 375 km altitude from June 1976 to late 1978.