caption: Two-dimensional clustering of 14 tissue experiments and transcripts that showed variation during epinephrine infusion. The set of genes were selected from the data matrix provided by the hybridization of 14 human tissues to a common reference pool. Experiments and responsive genes were grouped by hierarchical clustering after centering the log2 ratios on the mean for all experiments. Each row represents a single gene and each column an experimental sample. For each sample, the ratio of the abundance of the transcripts of each gene to the mean abundance across all experiments is represented by the color of the corresponding cell in the matrix file. Green boxes represent transcript levels lower than the mean. Red boxes are transcript levels higher than the mean, black boxes transcript level equal to the mean, and gray lines are missing data. Each node of the gene dendrogram was analyzed, and we focused on sets of genes clustered by functions. The upper dendrogram shows similarities in the expression pattern between tissues. A, Genes highly expressed in heart. Genes boxed in green have been shown to be expressed in skeletal muscle. B, Genes highly expressed in leukocytes and lymphocyte-producing tissues. Genes boxed in green encode secreted peptides.