MELATONIN SECRETION AND EXCRETION IN PATIENTS WITH OBSTRUCTIVE SLEEP-APNEA SYNDROME

Melatonin (MT) secretion and excretion were investigated in patients w ith obstructive sleep apnea syndrome (OSAS), Nine men, mean age 55.1 y ears, mean body mass index 31.2, with a previously confirmed diagnosis of moderate to severe OSAS, were tested on two occasions: immediately before initiation of continuous positive airway pressure (CPAP) treat ment and again after at least 4 weeks of continuous nocturnal use of C PAP. Serum MT concentrations were determined every second hour between 2000 and 0800 hours. Urine was collected between 2200 and 0700 hours for determination of urinary MT excretion. Sleep apnea recordings incl uded ear oximetry, respiration and body movements, body position, and breathing sounds. Nine healthy male controls were tested on one occasi on. We found that the MT secretion, as reflected by the area under the curve (AUC), among the OSAS patients did not differ from that found i n healthy controls (MT AUC 1.68 vs. 1.92 nmol/l x h). Sleep apnea reco rdings were normalized during CPAP treatment Moreover the excessive da ytime sleepiness disappeared in all patients. Neither MT secretion (MT AUC 1.68 vs. 1.56 nmol/l x hi nor urinary excretion of MT (0.122 vs. 0.108 nmol/9 h) changed significantly as a result of the CPAP treatmen t.