The physiological activity and in vivo distribution of dinitrosyl dithiolato iron complex

Nitric oxide (NO) is recognized as an endogenous mediator of vascular tone, a neurotransmitter and an immune effector molecule. Furthermore, it has been implicated in the development of various diseases. Because NO is extremely labile in the biological milieu, its activities can be effected not only by NO itself but also by relatively stable physiologic NO carriers or NO donors. Dinitrosyl iron complexes have been recognized as endogenous NO carrier molecules as well as S-nitrosothiols. The complex has been found in cells and the tissues of mammals and bacteria via its readily detectable, characteristic electron paramagnetic resonance (EPR) signals. Endogenously produced dinitrosyl iron complex with thiolate ligands (DNIC) has a critical biological potential; and it can function as a physiologic regulatory factor in a biological system, especially the immune and cardiovascular systems. We have been studying the in vivo behavior and distribution of DNIC to elucidate its physiological roles and pharmacokinetics. In this article, an attempt is made to provide an overview of the history, physiology and in vivo behavior of DNIC.