SLC39A5 and Zinc deficiency: This possibility is potentially supported by the results showing that both ZNT1 and MT were degraded when MDCK cells were treated for 6 h with a zinc chelator, N,N,N',N'-tetrakis(2-pyridylmethyl)ethylenediamine (TPEN), to rapidly cause zinc deficiency while maintaining Zip4 and Zip5 expression (Suppl.