Astrocytes Synthesize and Secrete α2-Macroglobulin: Differences Between the Regulation of α2-Macroglobulin Synthesis in Rat Liver and Brain
α2-Macroglobulin (α2M) is an important proteinase inhibitor both in the blood and in the interstitial space of many mammalian species. Recently, occurrence of α2M in human and fetal rat brain has been reported. However, its cellular origin remained obscure. Here it will be shown that astroglial cells cultured from newborn rats synthesize and secrete α2M. In addition to astrocyte primary cultures a rat astrocytoma cell line, C6-cells, also synthesize and secrete α2M. In contrast to hepatocytes of the adult rat, where α2M is expressed as an acute-phase protein and where glucocorticoids and monocyte-derived factors are required for its synthesis, α2M synthesis in astrocytes of newborn rats is independent from both. It is therefore concluded that expression of α2M is differently regulated in the liver of the adult rat and fetal or neonatal brain.
KeywordsMigration Polypeptide Glucocorticoid Hepes Plasminogen
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