POLYAMINES: DEVELOPMENTAL ALTERATIONS IN REGIONAL DISPOSITION AND METABOLISM IN RAT BRAIN¹

Abstract

Abstract The polyamines spermidine and spermine and the activity of the polyamine synthesizing enzyme, S ‐adenosyl‐L‐methionine (SAM) decarboxylase, were measured in regions of adult rat brains and during postnatal development. In the adult, although spermidine levels tended to correlate with the relative amounts of white matter in some areas, there were striking exceptions. SAM decarboxylase activity of the adult brain was higher than in most other mammalian tissues, although brain levels of polyamines were among the lowest. SAM decarboxylase activity appeared to be localized to cellular cytoplasm. Its activity increased with age in contrast to the levels of spermine, spermidine, DNA and RNA which decreased during postnatal development.