The effects of ductal obstruction on the acinar cells of the parotid of cat.

Twenty-nine parotids ligated for between 1 and 365 days were examined by light and electron microscopy. Major changes in the acini were seen at 4 days and included vacuolation, disintegration, extravasation, apoptosis, phagy and a reduction in number and size of secretory granules. There was a further reduction in secretory granules from 7 to 12 days, but acinar cells persisted even up to 365 days, some contained a luminal concentration of small secretory granules and occasionally acinar cells of a similar appearance to normal were found. These findings contrast with a reported absence of acinar cells from the obstructed parotid of rat and show that parotid acinar cells are able to persist and retain an appearance indicative of secretory activity.