Dynamic uptake of radioactive substance in rat salivary gland following 3H-melatonin administration.

Dynamics of radioactive accumulation in rat greater salivary gland following systemic administration of 3H-melatonin was studied to determine a possible action of the hormone in the gland. Progressive decline of 3H-melatonin concentrations was found in the serum, lung, skeletal muscle, liver, kidney, and salivary gland during 60 min following the administration. On the contrary, there was a progressive accumulation of radioactive substance other than 3H-melatonin in the salivary gland but not in other tissues mentioned. The radioactivity was also progressively and preferentially localized in the nuclear fraction of the gland cells. These results suggest a possible direct action of melatonin derivative in rat salivary gland.