[Circadian rhythms of pineal gland melatonin-forming function in healthy elderly people].

Circadian rhythms of pineal gland melatonin-forming function were studied in healthy elderly people (n=31, age range 60-74 years). The blood plasma melatonin concentration was determined by means of radioimmune method at 3.00, 9.00, 15.00 and 21.00. The study revealed two types of circadian rhythms of plasma melatonin concentration: a high-amplitude (29%) and a low-amplitude (71%) ones. The high-amplitude rhythm of melatonin-forming pineal gland function was observed in elderly people with a higher physical working ability and a lower functional age of cardiovascular system. It is advisable to conduct the correction of pineal gland melatonin-forming function in elderly people with low-amplitude circadian rhythm of plasma melatonin concentration.