Induction of melatonin synthesis in Tetrahymena pyriformis by hormonal imprinting--a unicellular "factory" of the indoleamine.

Melatonin is present in Tetrahymena and its synthesis can be enhanced by pretreatment (imprinting) with melatonin. Two days after imprinting melatonin level is elevated in the cells and more elevated in the supematant. Such a minute quantity, as 10(-12) M melatonin for 1 hour is able to provoke imprinting, however the effect is more expressed using 10(-6) M.

Melatonin in the unicellular Tetrahymena pyriformis: effects of different lighting conditions.

Melatonin content in the cellular fraction and medium of Tetrahymena pyriformis GL cultures was measured at different time points of light and dark exposures. Tetrahymena produced, stored and secreted immunoreactive melatonin, which in displacement and HPLC studies, behaved like synthetic melatonin. There was not a continuous secretion of melatonin produced by the cells.