Regeneration of the Guinea Pig Parotid Gland after 4-hydroxyaminoquinoline-1-oxide-lnduced Necrosis (39503)

A single iv injection of 4-hy-droxyaminoquinoline-1-oxide (4-HAQO) in a dose of 22 mg/kg body weight induced marked necrosis of parotid acinar tissue in guinea pigs within 48 hr. After the necrotic phase, marked regenerative activity of the acinar cells was noted. [³H]Thymidine auto-radiographic studies revealed a labeling index of 15% cells in the parotid gland at 72 hr after 4-HAQO injection. A significant increase in the mitotic activity of the parotid acinar cells was also evident at 72 and 78 hr after 4-HAQO administration. The acinar cell repair, as well as formation of the new acini, were complete at 108 hr. It is clear from the studies that 4-HAQO, a pancreati-cotoxic agent and a potent carcinogen, also causes necrosis of the parotid acinar tissue, which is followed by regeneration and restitution.