[Disruption of circadian rhythms of biogenic amines in rat hypothalamus upon administration of 1,2-dimethylhydrazine].

Levels of norepinephrine (NE), dopamine (DA) and the main metabolite of serotonin 5-hydroxyindoleacetic acid (5-HIAA) have been measured in the suprachiasmatic nuclei (SCN), preoptic area (PA), and median eminence (ME) of hypothalamus of rats after sole subcutaneous injection of 1,2-dimethylhydrazine (SDMH). Circadian changes of DA in all the brain structures under study as well as of NE in PA were observed in the control group, their levels in the mornings being higher than in the evenings; a circadian change of 5-HIAA in SCN had an opposite tendency. Both the evening (11 p.