Organs from mice deleted for NRH:quinone oxidoreductase 2 are deprived of the melatonin binding site MT3

FEBS Lett. 2004 Dec 3;578(1-2):116-20. doi: 10.1016/j.febslet.2004.10.083.


Two melatonin receptors (MT1 and MT2) have been cloned. A third melatonin binding site, MT3, is known with remarkable and distinct pharmacological properties. We previously reported the purification of MT3 and identified it as the enzyme dihydronicotinamide riboside:quinone reductase 2 (NQO2). To investigate the relationship between NQO2 and MT3, we generated a NQO2-/- mouse strain. These mice no longer present MT3 binding sites as measured with 2-[125I]-iodo, 5-methoxycarbonylamino-N-acetyltryptamine, the specific MT3 radioligand. These data establish NQO2 as part of the MT3 binding sites in vivo and resolve the matter of the nature of the third melatonin binding site.

MeSH terms

  • Animals
  • Binding Sites
  • Brain / metabolism*
  • Gene Targeting
  • Iodine Radioisotopes / metabolism
  • Kidney / metabolism*
  • Melatonin / metabolism
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Quinone Reductases / genetics*
  • Quinone Reductases / metabolism*
  • Radioligand Assay
  • Receptors, Melatonin / genetics
  • Receptors, Melatonin / metabolism*


  • Iodine Radioisotopes
  • Receptors, Melatonin
  • NRH - quinone oxidoreductase2
  • Quinone Reductases
  • Melatonin