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

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.

Polyamines in the Developing Mouse Brain

“…The developmental pattern of the polyam ines in the mouse brain are similar to those re ported previously for the rat brain [26] and are consistent with the timing in the develop mental changes in ornithine decarboxylase and S-adenosylmethionine decarboxylase ac tivities in the rat brain [3].…”

“…As reported here for the mouse, and by others in the rat [3,26], putrescine concentration peaks at day 5 but subsequent ly declines prior to the decrease in ornithine decarboxylase activity and to later peaks in spermidine and spermine concentrations. The initial decrease in putrescine levels may be due to an incorporation of the putrescine moiety into spermidine and spermine.…”

“…The possible association of the polyamines with the nucleic acids has yielded inconsistent and inconclusive results in both this study and previous studies [24,26]. In the developing rat parietal cortex, Shaskan et al [26] report ed a higher correlation of spermidine concen tration with DNA (r=0.93) than with RNA (r=0.76) while spermine was correlated more closely with RNA (r=0.75) than with DNA (r=0.62).…”

“…The later large increase in midbrain spermidine levels also supports pre vious evidence for a role of spermidine in myelin [4], In contrast to the other brain tissues exam ined, the cells of the rat cerebellum are pro duced during the first 3 weeks postnatally, with the major increase in cerebellar DNA occurring between 5 and 20 days after birth [2,26], Thymidine kinase activity and RNA concentration also peak during the second postnatal week [2,26]. The later decrease in DNA concentration and increase in protein concentration appear to be indicative of cel lular hypertrophy and maturation [2,26] and are similar to the changes reported here for the mouse cerebellum.…”

A Rapid and Simple Determination of Histamine and Polyamines

“…Another reason is that the cerebellum had been removed from the brain in the previous experiment. The cerebellum contains the highest polyamine level of all brain regions (6). When using the whole brain, both methods (CM-cellulose and P-cellulose column chromatography) showed the same levels of polyamines.…”