Sulphatoxymelatonin excretion in older people: Relationship to plasma melatonin and renal function

Baskett JJ, Cockrem JF, Antunovich TA. Sulphatoxymelatonin excretion in older people: Relationship to plasma melatonin and renal function. J. Pineal Res. 1998; 24:58–61. © Munksgaard, Copenhagen Abstract In order to validate measurement of urinary sulphatoxymelatonin as an accurate method of estimating plasma melatonin secretion in older people, we compared 24 h plasma melatonin secretion and sulphatoxymelatonin excretion with renal function in 20 subjects 62–89 years of age. There was a good correlation between plasma and urinary sulphatoxymelatonin over the same 24 h period (R2= 0.797) and no relationship between creatinine clearance and sulphatoxymelatonin excretion (R2= 0.075). The results suggest that sulphatoxymelatonin excretion estimation is a good surrogate measurement of plasma melatonin secretion in older people, at least across the range of creatinine clearance for the subjects in the study, 0.41–1.81 ml/sec.