Metallothionein (MT) mRNA levels were determined following exposure of neonatal rat primary astrocyte cultures to acidosis. Astrocyte total RNA was probed on northern blots with [α32P]dCTP-labeled synthetic cDNA probes specific for rat MT isoform mRNAs. The probe for MT-I mRNA hybridized to a single mRNA with a size appropriate for MT, approximately 550 nucleotides. MT-I mRNA levels in astrocyte monolayers exposed to pH 6.5 and 6.0 for 3 or 6 hours were unchanged compared with MT-I mRNA levels in control cultures exposed to pH 7.4. In contrast, 9 hour exposure of astrocytes to pH 6.5 and 6.0 led to a significant increase in MT-I mRNA transcripts compared with controls maintained at pH 7.4 (p<0.001 and p<0.02, respectively). A probe for MT-II mRNA that hybridizes to a single mRNA (450 nucleotides) was also used to determine the effect of acidosis on astrocyte MT-II mRNA transcripts. Although statistical significance was not attained, a similar trend was noted, with a 9 hour exposure to pH of 6.5 and 6.0 resulting in increased astrocytic expression MT-II mRNA compared with control cells maintained at pH 7.4. Acidosis was also associated with a pH-dependent increase in astrocytic volume. Accordingly, acidosis is invoked as an added stimulus to stress factors associated with the induction of astrocytic MT mRNA transcripts.
|Original language||English (US)|
|Number of pages||10|
|State||Published - Apr 15 1998|
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