Early gene expression in salivary gland after isoproterenol treatment

Isoproterenol, a β-adrenergic agonist, has been shown to induce salivary gland hyperplasia. To gain a better understanding of the underlying molecular changes altered by isoproterenol, microarray-based gene expression analysis was conducted on rat parotid glands at 10, 30, and 60 minutes after isoproterenol injection. After isoproterenol treatment, the number of differentially expressed genes was increased in a time-dependent manner. The regulation of up- and down-expression of genes related to cell proliferation/survival provides a better understanding of the mechanism of isoproterenol-induced parotid gland enlargement. For the time-course experiments, male Sprague-Dawley rats (2-3 months old) were injected intra-peritoneally with isoproterenol (20 mg/g body weight) or normal saline (control). The rats were euthanized at the indicated times and the harvested parotid glands stored at -80C until analyzed. Cells were harvested and processed at the following times: control (saline), immediately after treatment (10 min) and at 30 and 60min after treatment.