Fluorescence-displacement from the median eminence towards the arcuate nucleus at puberty.

The transition from infancy to adulthood is characterized by a sequence of events which are not yet fully understood. Hormonal changes influencing neuronal circuits in various hypothalamic area are--at least in part--held responsible. Using catecholamine fluorescence techniques in rats it has been found that a displacement of dopaminergic cells can be seen; the fluorescence activity shifting from the median eminence at day 20 after birth to the dorsolateral part of the arcuate nucleus around day 45 after birth, as is the case for catalase positive cells in these areas. It is concluded that the displacement of at least two populations of cells from the median eminence to the arcuate nucleus runs parallel to the onset of puberty. The relation of this shift in respect to the suprachiasmatic-preoptic control will be discussed.