MELATONIN INCREASES NERVE GROWTH-FACTOR IN MOUSE SUBMANDIBULAR-GLAND

The effect of melatonin administration on nerve growth factor (NGF) wa s studied in the submandibular glands of adult Swiss male mice. Melato nin injection, at 1 mu g daily for 30 days, resulted in an increase in the NGF content as detected by immunohistochemistry. The submandibula r gland weight and the area of the granular convoluted tubules, which contained NGF, were also increased significantly. These effects were n ot observed when the dose of melatonin was increased to 10 and 50 mu g daily. None of the melatonin treatments used influenced the weights o r histology of the testes or seminal vesicles of the mice. The results suggest that melatonin, at physiological concentrations, directly reg ulates NGF synthesis in the mouse submandibular gland.