inhibited by REDD2, a protein clo sely sellekchem related to REDD1. Expression of REDD1 is upregulated by FOXO1, as is that of 4EBP1, which inhibits translation by reducing the initiation of CAP dependent translation by eIF4E. We have recently found that administration for 7 days of the anabolic steroid nandrolone reduced denervation atrophy Inhibitors,Modulators,Libraries when begun 29 days after nerve transection associated with reduced levels of mRNA for MAFbx and MuRF1, but without changes in expression of IGF 1, its receptor, or IGF 1 binding proteins 2, 3, 4 or 5. However, when begun at the time of denerva tion, administration of nandrolone for the same 7 day period did not prevent atrophy or reduce expression of MAFbx or MuRF1. The molecular mechanisms by which nandrolone slows atrophy at 35 days are unclear.

While MAFbx and MuRF1 accelerate denervation atrophy in mice and degrade several proteins that determine muscle mass, their levels do Inhibitors,Modulators,Libraries not necessarily correlate to the response to interven tions that spare muscle. Thus, there are likely to be additional actions of nandrolone that contribute to its protective effects on denervated muscle at 35 days. In addition, the molecular determinants that prevent the anabolic Inhibitors,Modulators,Libraries actions of nandrolone at 7 days are unknown. We reasoned that comparison of genes regulated by nan drolone at 7 and 35 days would permit identification of those genes regulated only at 35 days, and which are thus likely to be associated with protection against atrophy.

Addi tionally, we predicted that the changes in gene expression in denervated muscle between 7 and 35 days formed the basis for the increased responsiveness to nandrolone at 35 days, because many actions of nandrolone involve its binding to the androgen receptor, a transcription factor that is activated when drug or hormone are Inhibitors,Modulators,Libraries bound, we predicted that there were changes over this period in the expression of genes encoding factors that either promoted or prevented transcriptional activity of the AR at target genes. Here, we have tested these possibilities using oligonucleotide microar rays with verification of the expression of selected genes by real time PCR and Western blotting. Results Filtering of microarray data Probesets representing 124 known genes were altered by nandrolone in denervated gastrocnemius at 7 days after nerve transection. At 35 days, nandrolone changed the expression of 276 genes in denervated gastrocnemius muscle.

Before comparing Pools A and D, we examined the possible confounding effects of changes in gene expres sion over time due to the effects of denervation on skele tal muscle. A comparison of gene expression in denervated gastrocnemius muscle Brefeldin_A from animals adminis tered vehicle revealed 318 unique genes that were altered at day 35 www.selleckchem.com/products/Y-27632.html as compared to day 7. Among these, 154 were also present in Pool D and were altered in the same direction by time and nandrolone. These genes were removed from Pool D, resulting in a new Pool B with 122 genes. Surprisingly, only 20 genes in Pool A w