頭蓋内腫瘍患者のメラトニン分泌能

MELATONIN SECRETION IN INTRACRANIAL TUMOR

　メラトニン（MLT）は，主として松果体で産生されるホルモンでありその産生と分泌に日周期リズムが証明されている。松果体部周辺腫瘍患者においてメラトニン分泌量と日周期リズムの変動を示唆する報告がある。我々はCTスキャン上中心構造物の対側偏位を伴う慢性頭蓋内圧亢進症状を呈した天幕上頭蓋内腫瘍患者6例（22-40歳）においてメラトニン分泌量およびその分泌パターンについて男性6例，女性4例（18-35歳）の健康人を対照として比較検討した。末梢血を6時間毎に4回採取した血漿中のMLTをSEP^®-PAK₁₈カートリッジを用いて分離抽出しBSAと結合させた1-（4-carboxybutyl）-melatoninを抗原として得られた家兎血清と83.9Ci/mmolの比放射能を持つ³H-MLTを使用したRIAによりMLTを測定した。対照群の血漿MLT濃度は14時，42.5±7.0pg/mL（Mean±SEM，n＝10）；20時，50.9±8.2pg/mL；02時，165.1±22.7pg/mL；08時，49.1±5.4pg/mLで日周期リズムが確認された。対象群のMLT濃度は，14時，19.8±6.2pg/mL（Mean±SEM，n＝6）；20時，15.9±5.2pg/mL；02時，52.0±17.2pg/mL；08時，20.3±3.5pg/mLであり，対照群と比較して有意の低下（P＜0.01）を示し，6例中4例（67％）に日周期リズムの消失を認め，メラトニン生合成に関する神経調節機構に何らかの障害が示唆された。

　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 healty 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 radioimmunaossay (RIA).

　(Method : The extracted MLT, the antiserum and the ³H-MLT were incubated overnight at 4℃, the antibody-combined and free ³H-MLT were separated using anmonium sulfate, and the radioactivity of the precipitate containing combined ³H-MLT was measured by licuid scintillation.) Plasma MLT concentrations of controls were 42.5±7.0 (Mean ± SEM) pg/m/ at 14 hr, 50.9±8. 8.2 pg/ mlat 20 hr, 165.1±22.7 pg/m/ at 02 hr, and 49.1±5.4 pg/m/ at 08 hr. The value of 14 hr. significantly differed from 02 hr, (P ＜ 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＜0.01) except at 14 hr. (P＜0.05), showing no diurnal rhythmexcept 2 cases.

　In conclusion, in ICT with midline shift of CT scan melatonin secretion was inhibited and diur-nal rhythm disappeared in four cases (67%).