Journal of neurochemistry
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Journal of neurochemistry · Sep 1991
Comparative StudyGlucocorticoids regulate the synthesis of glial fibrillary acidic protein in intact and adrenalectomized rats but do not affect its expression following brain injury.
Short (5 days)- to long-term (4 months) corticosterone (CORT) administration by injection, pellet implantation, or in the drinking water decreased glial fibrillary acidic protein (GFAP) by 20-40% in hippocampus and cortex of intact rats. In contrast to CORT, adrenalectomy (ADX) caused elevations (50-125%) in hippocampus and cortex GFAP within 12 days of surgery that persisted for at least 4 months. CORT replacement of ADX rats decreased GFAP amount in hippocampus and cortex. ⋯ Thus, glucocorticoids and injury appear to regulate the expression of GFAP through different mechanisms. In contrast to the lack of effects of CORT on brain damage-induced increases in GFAP, CORT treatment begun in 2-week ADX rats, after an increase in GFAP had time to occur, did reverse the ADX-induced increase in GFAP. These results suggest that the increase in GFAP resulting from ADX is not mediated through an injury-linked mechanism.