Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Pivot Concepts:
Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Target Concepts:
Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Query: EC:4.1.1.17 (
ornithine decarboxylase
)
6,351
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
The biochemical development of rotation-mediated aggregating brain cell cultures was studied in a serum-free chemically defined medium in the presence (complete medium) or the absence of triiodothyronine (T3). The expression of 2',3'-cyclic nucleotide 3'-phosphodiesterase (CNP) and
myelin basic protein
(
MBP
), two myelin components, was temporally dissociated in brain cell aggregating cultures grown in a complete medium. CNP increased from day 8 and reached a plateau around day 25.
MBP
accumulated rapidly from the third until the fourth week in culture. The total protein content increased gradually until day 25. The activity of
ornithine decarboxylase
(
ODC
) used as an index of cell growth and differentiation, showed two well-defined peaks of activity. The first peak reached a maximum at day 6 and correlated with both the highest DNA content and the peak of [3H]-thymidine incorporation. The second peak of
ODC
activity (from day 19 to 35) coincided with the differentiation of oligodendrocytes. These results confirm that aggregating fetal rat brain cells cultured in a serum-free chemically defined medium undergo extensive differentiation. Addition of T3 to the culture medium doubled the CNP activity by day 16. In contrast,
MBP
was only slightly increased by day 16, reaching at 25 and 35 days 8 to 10-fold higher values than the untreated cultures. When T3 was removed between day 16 and 25, CNP decreased almost to control values and
MBP
failed to accumulate. Moreover, when T3 was reintroduced into the medium (between day 25 and 35), CNP activity was restored and
MBP
content was partially corrected. T3 treatment produced a concentration-dependent increase in
ODC
activity which was observed only around day 19. The first peak of
ODC
activity observed at culture day 6 was independent of the presence of T3. These results obtained in brain cell cultures emphasize the direct effect of T3 on myelination.
...
PMID:Triiodothyronine stimulation of oligodendroglial differentiation and myelination. A developmental study. 241 94
Bovine growth hormone (bGH) and epidermal growth factor (EGF) increased the activity of
ornithine decarboxylase
(
ODC
) in brain cell aggregates cultured in a serum-free chemically defined medium.
ODC
is considered as a marker of cell growth and differentiation. The effect of bGH and EGF on myelination was investigated by measuring two myelin markers, 2',3'-cyclic nucleotide 3'-phosphodiesterase (CNP) and
myelin basic protein
(
MBP
). EGF treatment at days 2 and 5 caused a dose-dependent increase of both myelin markers at culture day 12. This increase could still be observed at culture day 19, indicating a prolonged action of EGF. The continual presence of bGH in the culture medium produced a large accumulation of
MBP
at day 19. This effect was dose-dependent and required the presence of triiodothyronine (T3). In contrast, the effect of bGH on CNP activity did not require the presence of T3. This is the first report showing a direct effect of bGH on CNS myelination in vitro and of EGF on both
MBP
accumulation and
ODC
activity.
...
PMID:Epidermal growth factor and bovine growth hormone stimulate differentiation and myelination of brain cell aggregates in culture. 241 55
The influence of dexamethasone on the development of neurons and oligodendrocytes was studied in serum-free, aggregating rat brain cell cultures. Synaptogenesis and myelination occur in this culture system. The concentration of
myelin basic protein
and the activity of 2',3'-cyclic nucleotide 3'-phosphodiesterase were used as oligodendroglia and myelin markers. Choline acetyltransferase and acetylcholinesterase served as neuronal markers, glutamine synthetase reflected astrocyte differentiation, while
ornithine decarboxylase
served as a general marker for cell growth and maturation. This study showed that dexamethasone stimulated the differentiation of cholinergic neurons and astrocytes. The effect of dexamethasone on oligodendroglial differentiation and myelination depended on the stage of development: during the early phase of myelination dexamethasone had a stimulatory effect, whereas at a later stage it showed a significant inhibition.
...
PMID:Dexamethasone stimulates the biochemical differentiation of fetal forebrain cells in reaggregating cultures. 242 5
