Oxytocin revisited: It is also a cardiovascular hormone.

Oxytocin (OT), traditionally associated with reproductive functions, was revisited recently, which revealed several new functions of the hormone in cardiovascular regulation. To support this contention, we have demonstrated the presence and synthesis of OT receptors in all heart compartments and the vasculature. The functionality of these receptors has been established by the ability of OT to induce atrial natriuretic peptide and nitric oxide (NO) release from the perfused heart and atrial slices. OT's cardiovascular actions include natriuresis, blood pressure reduction, negative inotropic and chronotropic effects, parasympathetic neuromodulation, as well as vasodilatation triggered by the NO pathway that is also involved in endothelial cell growth and anti-inflammatory activity. In addition, we have reported the abundance of the OT system in the early developing heart and OT's capacity to generate cardiomyocytes from mouse embryonic stem cells. The most potent inducer of cardiac differentiation, OT-Gly-Lys-Arg, is an extended form of OT that is abundantly expressed in the fetal heart. Therefore, in pathological conditions, OT plays an anti-inflammatory and cardioprotective role, improving vascular and metabolic functions; it has potential for therapeutic use.