CIRCADIAN RHYTHM OF PINEAL GLAND MELATONIN-FORMING
Circadian fluctuations were studied in melatonin and cortisol concentrations and serum thymic factor (FTS) titers in patients with esophageal andcardiac cancer aged between 50 and 73 years. It is shown that 45% patients feature a considerably increased melatonin levels in the evening (9.00 p. m.) compared to morning (9.00 a. m.). This pattern is similar to that in healthy subjects. In 55% patients, evening melatonin levels remained unchanged or even decreased. In patients with preserved rhythm of pineal gland melatonin-forming function, FTS titers increased considerably in the night- time. In case of a changed rhythm of the pineal gland function, FTS titer remained unchanged round the clock. Theday-nightdifferentials in cortisol concentrations were more considerable in patients with a changed rhythm of the pineal gland function compared to those with the unchangedrhythm. Possible mechanism sof the deviations in the circadian relationships of the functional state of the pineal gland, thymus, and adrenal cortex in cancer patients are discussed.