Boonsirm WithyachumnarnkulMookda LimpanawattanakulWantanee TrakulrungsiMahidol University2018-02-272018-02-271986-05-12Life Sciences. Vol.38, No.19 (1986), 1757-1765002432052-s2.0-0022547224https://repository.li.mahidol.ac.th/handle/20.500.14594/9868Radioactive concentrations were determined in serum, lung, hypothalamus, anterior pituitary, testis, and accessory sex organs of adult male rats at 2, 20, 30 and 60 min after intravenous 3 H-melatonin administrations. The retention patterns of 3 H-melatonin and other radioactive substance ( 3 H-non-melatonin) in these tissues were compared. The anterior pituitary demonstrated best tissue retention with highest concentration of 3 H-melatonin. The testis and prostate gland accumulated 3 H-non-melatonin in an increasing manner from 2 to 60 min. The radioactive substances were also preferentially and progressively located in the nuclear fraction of the anterior pituitary, hypothalamus, testis, and prostate gland. This study leads to the following suggestions: (1) the anterior pituitary is another target organ of melatonin; (2) melatonin is converted into other active material which exerts its action in the testis and prostate gland; (3) melatonin and its active derivative exert their action through the nuclei of their respective cells. © 1986.Mahidol UniversityPharmacology, Toxicology and PharmaceuticsArticleSCOPUS10.1016/0024-3205(86)90126-8