Stat1 in developing and adult rat brain. Induction after transient focal ischemia.

Stat1 has a dual function as signal transducer and activator of transcription, and is activated in response to growth factors and cytokines. We examined Stat1 in the rat brain during development and following transient focal ischemia, using Western immunoblotting. Two bands of 91 and 84 kDa, corresponding to Stat1 alpha and Stat1 beta forms, were found with an intensity that increased from postnatal day 0 to adulthood in cerebellum and cerebral cortex. Ischemia caused a strong induction of Stat1 in the ipsilateral cortex after 4, 7 and 15 days, but not at 6 or 24 h. These results show that Stat1 is normally expressed in the postnatal and adult rat brain and is induced under brain infarction.