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Possible Involvement of Humoral Regulation in the Effects of Elevated Cerebral 4‐Aminobutyric Acid Levels on the Polyamine Metabolism in Brain
Author(s) -
Lapinjoki Seppo P.,
Pulkka Anitta E.,
Laitinen Seppo I.,
Pajunen Antti E. I.
Publication year - 1983
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1983.tb04794.x
Subject(s) - gaba transaminase , polyamine , metabolism , ornithine decarboxylase , transaminase , endocrinology , medicine , in vivo , chemistry , biochemistry , enzyme , glutamate decarboxylase , biology , pharmacology , microbiology and biotechnology
It has been reported in several recent studies that the manipulation of cerebral 4‐aminobutyric acid (GABA) level results in unexpected changes in the cerebral polyamine metabolism in vivo . The mechanisms behind these interactions have remained unknown. The present results show that the changes in polyamine metabolism are not limited to the brain, but are observable also in the liver, which served as a peripheral reference tissue. Different types of responses in the activities of the poiyamine‐synthesizing enzymes, ornithine decarboxylase and adenosylmethionine decarboxylase, were observed after increasing the cerebral GABA concentration of mice with varying doses of two GABA transaminase inhibitors, gabaculine and ethanolamine‐ O‐ sulphate. The time course of the significant changes in the enzyme activities showed significant correlation between the brain and liver. The possibility of direct effects of the drugs on liver was excluded by injecting them intracerebroventricularly, and by performing control experiments with equal doses given peripherally. It is concluded that the observed changes in the polyamine metabolism of liver are produced through centrally mediated humoral regulation, and that the corresponding changes in the brain are obviously due to the same factor or factors, since they are significantly correlated to the changes in liver.