Kennaway D J, Voultsios A
Department of Obstetrics and Gynecology, University of Adelaide Medical School, South Australia.
J Clin Endocrinol Metab. 1998 Mar;83(3):1013-5. doi: 10.1210/jcem.83.3.4636.
The appearance of melatonin in saliva in concentrations up to 70% lower than those in blood has led to the suggestion that melatonin is bound to plasma protein and that saliva levels reflect the circulating free hormone. To test this directly, melatonin was measured in human plasma from 10 subjects after ultrafiltration through Centrifree micropartition tubes and compared to saliva melatonin levels in samples collected simultaneously. Melatonin was detected in the protein-free fraction and increased throughout the night in parallel with the saliva melatonin level. Peak concentrations ranged from 45-200 pmol/L (mean +/- SEM, 106 +/- 17 pmol/L) and averaged 23% of the total melatonin level. Across all samples, the correlation between the saliva levels and the free hormone levels was significant (r = 0.84; P < 0.05). These results provide the first direct evidence that endogenous melatonin is bound to plasma proteins and that saliva melatonin generally reflects the levels of this binding.
唾液中褪黑素的浓度比血液中的浓度低70%，这表明褪黑素与血浆蛋白结合，唾液水平反映了循环中的游离激素水平。为了直接验证这一点，对10名受试者的血浆进行超滤，通过Centrifree微分离管测量褪黑素，并与同时采集的唾液褪黑素水平进行比较。在无蛋白组分中检测到褪黑素，其在整个夜间与唾液褪黑素水平平行升高。峰值浓度范围为45 - 200 pmol/L（平均值±标准误，106±17 pmol/L），平均占总褪黑素水平的23%。在所有样本中，唾液水平与游离激素水平之间的相关性显著（r = 0.84；P < 0.05）。这些结果首次提供了直接证据，证明内源性褪黑素与血浆蛋白结合，且唾液褪黑素通常反映这种结合的水平。
