Isomer-to-ground-state ratios are measured for the group of photon- and α-induced nuclear reactions. The photonuclear reactions on high-spin isomeric targets - 178Hfm2 (16+) and 180Tam (9-) - were detected successfully. Results are analysed from the point of view of the K-selectivity manifestation for the level population. The yields comparison with the regular values confirms strong K-mixing at high excitations.