[en] In the study of the particle production process, using nuclear targets as detectors, results have been obtained which prompted to conclude that the particle production in hadron-nucleon collisions is mediated by intermediate objects created first. The existence of such objects should manifest itself in the elementary hadron-nucleon collisons as well. A search of appropriate effects testable experimentally has been performed in analysing of existing experimental data on the nucleon-nucleon collisions. In result, it can be concluded that: a) many such effects are known from numerous experiments in which nucleon-nucleon collisions have been studied; b) none of properties of the proton-proton collisions contradict the picture of the particle production process prompted by experiments with nuclear targets; c) the particle-producing nucleon-nucleon collisions may be treated in their early stage as 2 → 2 endoergic reactions