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Influence of culture conditions on monoamine oxidase A and B activity in rat astrocytes
Author(s) -
Carlo Pia,
del Rio Meris,
Violani Elisabetta,
Sciabà Luigi,
Picotti Giovanni B.
Publication year - 1996
Publication title -
cell biochemistry and function
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.933
H-Index - 61
eISSN - 1099-0844
pISSN - 0263-6484
DOI - 10.1002/cbf.645
Subject(s) - subculture (biology) , monoamine oxidase , fetal bovine serum , in vitro , enzyme , astrocyte , enzyme assay , chemistry , cell culture , biochemistry , microbiology and biotechnology , biology , endocrinology , botany , genetics , central nervous system
Astroglial cells dispersed from newborn rat hemispheres were established in medium supplemented with 20 per cent fetal calf serum (FBS) and then grown to a confluent monolayer in the presence of 10 per cent FBS or charcoal‐stripped FBS (CS). Type 1 astrocytes were subcultured and either maintained under the same conditions of the primary cultures or converted to serum‐free chemically defined medium (CDM). No differences were found in either MAO A or MAO B activity of astrocytes grown in the presence of FBS or CS after 15 and 21 days in vitro (day 1 and 6 of subculture). In contrast, on day 21 both MAO A and MAO B activities were markedly higher in astrocytes subcultured in CDM compared with cells maintained in serum‐supplemented medium. This difference appeared to be due to increased number of enzyme molecules, since kinetic analysis showed an increase in V max of both MAO isoenzymes in serum‐free medium, but no change in K m . Consistently, the recovery of MAO A and MAO B activity after irreversible enzyme inhibition by clorgyline and deprenyl was faster in CDM than in FBS‐supplemented medium, indicating enhanced enzyme synthesis under serum‐free condition. Estimates of half‐lives for the recovery of MAO A and MAO B activity indicated that, under both culture conditions, type A activity had a higher turnover rate than type B. The effect of CDM on astrocyte MAO does not appear to be due to selection of a subpopulation of cells, but rather linked to a morphological change (differentiation) with increased synthesis of both MAO isoenzymes.