We have demonstrated that entire oxytocin (OT) system is synthesized in the rat and human heart and this hormone is implicated in several cardiac functions including stem cells differentiation into cardiomyocytes. These observations led us to the invention of OT as an inducer of cardiomyogenesis (US20060205636A1). We also proposed the use of OT, its functional derivatives, and/or physiological precursors as well as nucleic acids capable of encoding OT as cell-differentiating and useful agents for treating or preventing diseases, such as heart diseases associated with loss of cardiomyocytes. The invention is relevant to the use of OT or OT-related compounds. OT is claimed as an inducer that promotes the differentiation of non-cardiomyocytes (e.g. stem/progenitor cells) in situ, which can be used to repair, restore or fortify damaged cardiac tissue or in cell culture in order to provide material for cell or tissue grafting in the heart. Recent reports documented the significant progress in the research on the role of OT in cardiovascular regulation. Most of the results are consistent with the postulated cardioprotective role of OT. In this review, new data are discussed in the context of the main points presented in the invention.