Prompt Recovery of Damaged Adrenal Medullae Induced by Salinomycin

The morphologic changes in the adrenal medullae of rats treated with an ionophore antibiotic, salinomycin, are described. Male rats of approximately 7 wk of age were treated orally with a single dose of salinomycin at 80 mg/kg body weight. Following this treatment, the adrenal glands were examined, using immunohistochemistry, for neurofilament, laminin, fibronectin, and S-100 protein; the glands were also examined using transmission electron microscopy. One hour after the treatment, a karyopyknosis was observed in the clusters of affected chromaffin cells in which the neurofilament, laminin, and fibronectin were present. The lesions became progressively conspicuous between hours 5 and 10. Ultimately, the outcome was cell lysis. Five hours after salinomycin treatment, unaffected chromaffin cells strongly stained to tyrosine hydroxylase. At 10 hr, new chromaffin cells, which were irregular in shape with electron-dense cytoplasm (dark cell), that were strongly stained for tyrosine hydroxylase appeared at the...