Ethionine action on the rat pancreas: phospholipase levels and incorporation of the amino acid into phospholipases and phospholipids.

Ethionine intoxication induces a decrease of the pancreatic content of prophospholipase and chymotrypsinogen in the rat. On the other hand, there is an increase in the level of the intracellular zymogenless phospholipase. Ethionine is incorporated into pancreatic proteins, we therefore examined whether this amino acid might be incorporated into the zymogenless phospholipase. The purification of this enzyme after the injection of l -[1,2- ethyl - 14 C]ethionine showed that it was labeled. After an ip injection of l -[1,2- ethyl - 14 C]ethionine and l -[1- methyl - 14 C]methionine, we found that pancreatic phosphatidylcholines incorporated the ethyl - 14 C from ethionine, but more slowly than the methyl - 14 C from methionine. Pancreatic phospholipase A 2 is able to hydrolyze the phosphatidylcholine containing ethyl - 14 C.