[5-Methoxy-N-acetyltryptamine (melatonin) in enterochromaffin cells].

As evidenced from the action of acetone extracts of the mucous layer of the human appendix, these extracts contain a substance capable of bleaching the frog's skin. Model experiments with 0.1% adrenaline, 0.2% noradrenaline, 2.5% hydrocortisone and solutions of various concentrations of synthesized melatonin permitted to identify the above substance as melatonin. The bleaching aciton dependence on the number of enterochromaffin cells (Ec-cells) in the mucous layer of the appendix, and the presence of serotonin in Ec-cells reveal a connection between melatonin and Ec-cells. An average content of 5-methoxy-N-acetyltryptamine in the human appendix amounts to 0.004 mg per 100 Ec-cells. It is suggested that the epiphysis and enterochromaffin cells compose a common functional neuroendocrine system playing a definite role in maintaining the homeostasis of the organism.