[Melatonin secretion in intracranial tumor]

The secretion of melatonin (MLT) was examined in 6 ICT patients, 2 men and 4 women, who showed marked midline shift of CT scan findings with intracranial hypertension signs (headache, nausea, vomiting). Their ages ranged from 22 to 40 years. The controls, 6 healthy men and 4 healthy women (follicular stage) were aged from 18 to 35. With the subject recumbent, blood was drawn at 14, 20, 02 and 08 hour (Lights out, 9 pm; sunrise, 6 am). After separation of plasma by centrifugation, MLT was extracted by SEP-PAK C18 cartridge and determined by radioimmunoassay (RIA). (

The extracted MLT, the antiserum and the 3H-MLT were incubated overnight at 4 degrees C, the antibody-combined and free 3H-MLT were separated using ammonium sulfate, and the radioactivity of the precipitate containing combined 3H-MLT was measured by liquid scintillation.) Plasma MLT concentrations of controls were 42.5 +/- 7.0 (Mean +/- SEM) pg/ml at 14 hr, 50.9 +/- 8.2 pg/ml at 20 hr, 165.1 +/- 22.7 pg/ml at 02 hr, and 49.1 +/- 5.4 pg/ml at 08 hr. The value of 14 hr. significantly differed from 02 hr, (P less than 0.01) showing a diurnal rhythm. The patients' MLT levels (pg/ml) were 19.8 +/- 6.2 at 14 hr, 15.9 +/- 5.2 at 20 hr, 52.0 +/- 17.2 at 02 hr, and 20.3 +/- 3.5 at 08 hr. These values were significantly lower than in controls (P less than 0.01) except at 14 hr. (P less than 0.05), showing no diurnal rhythm except 2 cases. In conclusion, in ICT with midline shift of CT scan melatonin secretion was inhibited and diurnal rhythm disappeared in four cases (67%).