Could oxytocin be helpful as it can bind free copper ions in the cells?
Copper and silver ions seem to impair LXR and FXR activation. This is not necessarily a good thing and could be a cause of symptoms seen in copper overload situations (e.g. Wilson's disease):
Together, these data demonstrate that copper-mediated nuclear receptor dysfunction disrupts liver function in WD and potentially in other disorders associated with increased hepatic copper levels.
Elevated copper impairs hepatic nuclear receptor function in Wilson’s disease
Is this still true when copper is bound to oxytocin?
In this work, we focus on characterizing copper and zinc bound forms of oxytocin and related analogs through far-UV circular dichroism. We report that Cu(II) and Zn(II) bind uniquely to oxytocin and all analogs investigated. Furthermore, we investigate how these metal bound forms may affect downstream signaling of MAPK activation upon receptor binding. We find that both Cu(II) and Zn(II) bound oxytocin attenuates the activation of the MAPK pathway upon receptor binding relative to oxytocin alone.
Metal-induced structural changes to a peptide hormone may have a number of effects on storage, secretion, stability, and/or signaling. In this case, it is possible that both Zn(II) and Cu(II) lend different structural integrities to oxOT at different points in oxOT lifetime. Physiologically, it is possible that Cu(II) is bound to oxOT in serum but, because the concentrations of metal ions surrounding specific tissues are believed to fluctuate, Zn(II) may be able to displace Cu(II) under specific concentrations. It still remains to be seen how Cu(II) would affect oxOT in serum, however, metal binding may be a key player in prevention of degradation; further studies in our lab are underway to test this hypothesis. The binding of metal ions to peptide hormones, particularly oxOT, may provide an additional source for regulation, and this study provides the foundation for future studies.
Investigation of metal modulation of oxytocin structure receptor-mediated signaling
It would be interesting to determine if such an effect (oxytocin binding to copper thus avoiding free copper to disturb FXR and LXR, or other nuclear receptors, activation) could be "significant" in terms of the number of moles of oxytocin with respect to the quantity of copper ions in a cell.