[Daily rhythms of melatonin in pineal, serum and urine of rats (author's transl)]

Abstract

The levels of melatonin in urine, serum, and pineals were determined in rats during the light/dark cycle. Previous to the radioimmunoassay, melatonin was isolated using a new ascending chromatographic method with programmed multiple development. The daily excretion of melatonin and its serum levels showed a characteristic rhythm, night samples containing several times more melatonin than those of the light period. The pineal content of melatonin of animals killed at different intervals also showed a similar day/night rhythm. The chromatographic method used gave a perfect separation of melatonin from other materials which could interfere in the assay. The mobility of material detected by RIA was identical to that of authentic melatonin chromatographed concurrently.