Left ventricular gene expression profiles from 12-, 16- and 20-months old spontaneously hypertensive rats (SHRs) were compared with left ventricular profiles seen in age-matched Wistar-Kyoto (WKY) rats by screening Affymetrix U34A arrays (there are 4 samples in each timepoint except 3 samples of 20-months old WKYs). Keywords: time-course