Uptake and subcellular distribution of 65zinc in brain structures during the postnatal development of the rat.

The uptake ratio of 65zinc into the postnatally developing hippocampal formation, cerebellum and remainder of the brain showed only minor differences, whilst following subcellular fractionation a marked decrease in 65zinc uptake from postnatal day 15 to adulthood was found in nuclear sediments (hippocampal formation 44.3%, cerebellum 27.5%), along with an increase in synaptosomal fractions on the hippocampal formation by 55.4% and of the cerebellum by 37.1%. The shift of zinc out of the perikarya into terminal fields during the postnatal development without substantial alterations of the net zinc content is supposed to be a consequence of a functional relation of zinc to synaptic transmission processes.