Effects of triamcinolone on brain and cerebrospinal fluid apolipoprotein E levels in rats

The effects of the short term administration of triamcinolone (0.5 mg per 100 g body weight, 5 days) on apolipoprotein E and A-I concentrations in cerebrospinal fluid (CSF), brain extract and serum were studied in male Wistar rats using enzyme immunoassays. ApoE was significantly increased by triamcinolone in apoE-rich HDL1 in serum; 40+/-13 (mean+/-SD) vs. 68+/-23 mg/dl (15 saline-treated rats vs. 11 triamcinolone-treated rats)(P<0.01), which was paralleled by an increase in serum apoA-I (76+/-21 vs. 184+/-24 mg/dl), while serum lipids also increased significantly. No significant difference was observed in the apoE concentrations in CSF (296+/-170 vs. 269+/-67 microg/dl) or brain extract (5.0+/-1.6 vs. 5.7+/-1.8 microg/g wet weight). The apoA-I concentrations found in CSF and brain extract were much lower than those for apoE and were not appreciably affected by triamcinolone: 7.7+/-5.5 vs. 4.5+/-3.1 microg/dl for CSF and <0.5 vs. <0.5 microg/g wet weight for brain extract. The apo E metabolism in the rat central nervous system appears to be refractory to the short term administration of triamcinolone and to changes in the serum lipoprotein metabolism. ApoA-I appears unlikely to play a significant role in the rat central nervous system.