Serum amylase of non-parotid and non-pancreatic origin increases on feeding in rats and may originate from the liver.

1. In order to evaluate possible non-salivary contributions to the content of salivary-type amylase in the circulation, parotid glands--the only salivary source of amylase in rats--have been totally removed and the effects on serum amylase have been assessed, after fasting and at different times after feeding. 2. Despite the parotidectomy the resting level of salivary-type amylase remained the same and an increase was still found to occur on feeding. 3. Isoelectric focusing has identified additional isoforms of amylase in serum and liver distinct from those occurring in parotid saliva. 4. The liver therefore may be contributing to the fasting levels of serum amylase and to the increases that occur on feeding, in rats.