Investigations on the Origin of Amylase in Serum and Urine

Abstract

The values for serum and urinary amylase do not change after subtotal pancreatectomy in man and after complete extirpation of the gland in dogs. Serum amylase and urinary amylase, therefore, cannot be of pancreatic origin under normal conditions. When the pancreatic ducts are ligated alone these enzymes become markedly increased. They rise further when secretin is injected. They fall to their original values when the pancreas is removed after duct ligation. The same effect is obtained by establishment of a pancreatic fistula after duct ligation; that is, urinary and serum amylase return to their original levels. Secretin given after establishment of the fistula does not affect the values for amylase in serum or urine. However, the amount of amylase secreted through the fistula is markedly increased. After hepatectomy alone, there is an increase of serum amylase in the first 4 to 6 hr. Six hours later the values drop to between 46 and 96 units. When pancreas and liver are removed at the same operation, serum amylase is elevated after 2 hr. Then the values fall to around 45 units until the death of the animals. When the liver is removed after the dogs have sufficiently recovered from the pancreatectomy, serum amylase decreased to values as low as 38 to 42 units in 12 to 16 hr until the dogs died. These results indicate that the amylase regularly present in serum and urine is not of pancreatic origin. Only those elevated amounts of amylase which appear in the urine and blood under pathological conditions are derived from the pancreas. Since the serum amylase decreases steadily after hepatectomy, the liver is to be considered as one of the sources of the amylase in serum.