[Phylogeny of peptide regulation: the beginning].

Analyzing existing literature sources and his own experimental data, the author has concluded that (i) regulatory peptides arise solely as a result of cleavage of protein precursors, but not by non-ribosomal synthesis; (ii) the peptide regulation of physiological functions emerged as a part of autocrine regulation system almost simultaneously with life itself; peptide paracrine regulation appeared in the colonial prokaryotes, and peptide endocrine regulation in the multicellular eukaryotes; (iii) the regulatory peptides and their receptors could occur either sequentially (in any order) or simultaneously; (iv) conservatism of the primary structure of regulatory peptides is not significantly different from that of proteins; (v) the regulatory peptides are presented in the most evolutionarily ancient species wider than specialists think.