The amount of 6-sulphatoxymelatonin, the chief metabolite of melatonin, in the urine was measured in nine patients, who were subjected to bilateral sympathectomy at the second thoracic ganglionic level for treatment of hyperhidrosis of the palms. All patients showed before surgery a normal 6-sulphatoxymelatonin excretion with a peak in the excretion
during the night time. After the sympathectomy, the high night time excretion was clearly abolished in five patients but remained high in four patients...
http://www.ncbi.nlm.nih.gov/pubmed/16647807