370
PETER BERNFELD
like pancreatic amylase, must be considered to occur in all vertebrates.
That amylase does not enter the blood stream through the pancreatic
duct has been concluded from experiments in which the concentration
of blood amylase of dogs, although eight to sixteen times increased a
few days after complete ligation of the pancreatic duct, returned to
normal between the sixth and eighth day (94).
(4). Urinary amylase. Urinary amylase is generally found in all
animal species having pancreatic amylase, and it is usually assumed
that the level of urinary amylase parallels the amylase activity of the
pancreas. Roe et al. (95) observed, however, that pancreatectomy of rats
is not followed by a decrease in the urinary enzyme and concluded that
the pancreas is not an important source for urinary amylase in the normal rat. This is in contrast to older reports according to which urinary
amylase is decreased after extirpation of the pancreas (96), but is increased after ligation of the pancreatic ducts (97).
(5). Liver amylase. Liver amylase has been reported in many animals (98), in particular in the dog and, in order of decreasing activity,
in swine and in rabbit and lamb (99); it has been identified as being an
a-amylase (100), but the last doubt about this enzyme being a phosphorylase has been removed by the work of McGeachin et al. (44),
who determined its activity in the absence of phosphate (see Table II).
(6). Intestinal amylase. Intestinal amylase was identified in histological sections of mucosa of the duodenum and ileum of the rat (101).
The amylase content of the Thiry-Vella juice of the dog was found to
increase with the starch content of the food, whereas the amylatic action
of the juice was the lower the farther away the fistula was from the
duodenum (102). Duodenal amylase levels were reported to be very
high in the rat, high in the mouse, and much lower in the guinea pig,
chicken, and dog (see Table IV). No amylase has been detected in the
duodenal juice of the sheep (103).
(7). Animal amylases from miscellaneous other sources. Many other
organs have been reported to contain α-amylase. Frequently, it is not
clear whether the starch or glycogen degrading activity should be
ascribed to a hydrolytic or a phosphorolytic enzyme. Repeated reports
have appeared in the literature stating that muscle contains amylase
besides phosphorylase (104, 105), although the amounts of muscle
amylase in the rat and mouse are very low (see Table II) (44). Amylase has been observed to occur in the kidney, heart, thyroid, and testes
(106). The amounts of amylase in the spleen, heart, kidneys, muscle,
brain, perirenal fat, and colon of the rat, mouse, guinea pig, dog, and
chicken have been tabulated by McGeachin et al. (44) (see Table IV)
and are very low compared to the amounts of pancreatic amylase.
PETER BERNFELD
like pancreatic amylase, must be considered to occur in all vertebrates.
That amylase does not enter the blood stream through the pancreatic
duct has been concluded from experiments in which the concentration
of blood amylase of dogs, although eight to sixteen times increased a
few days after complete ligation of the pancreatic duct, returned to
normal between the sixth and eighth day (94).
(4). Urinary amylase. Urinary amylase is generally found in all
animal species having pancreatic amylase, and it is usually assumed
that the level of urinary amylase parallels the amylase activity of the
pancreas. Roe et al. (95) observed, however, that pancreatectomy of rats
is not followed by a decrease in the urinary enzyme and concluded that
the pancreas is not an important source for urinary amylase in the normal rat. This is in contrast to older reports according to which urinary
amylase is decreased after extirpation of the pancreas (96), but is increased after ligation of the pancreatic ducts (97).
(5). Liver amylase. Liver amylase has been reported in many animals (98), in particular in the dog and, in order of decreasing activity,
in swine and in rabbit and lamb (99); it has been identified as being an
a-amylase (100), but the last doubt about this enzyme being a phosphorylase has been removed by the work of McGeachin et al. (44),
who determined its activity in the absence of phosphate (see Table II).
(6). Intestinal amylase. Intestinal amylase was identified in histological sections of mucosa of the duodenum and ileum of the rat (101).
The amylase content of the Thiry-Vella juice of the dog was found to
increase with the starch content of the food, whereas the amylatic action
of the juice was the lower the farther away the fistula was from the
duodenum (102). Duodenal amylase levels were reported to be very
high in the rat, high in the mouse, and much lower in the guinea pig,
chicken, and dog (see Table IV). No amylase has been detected in the
duodenal juice of the sheep (103).
(7). Animal amylases from miscellaneous other sources. Many other
organs have been reported to contain α-amylase. Frequently, it is not
clear whether the starch or glycogen degrading activity should be
ascribed to a hydrolytic or a phosphorolytic enzyme. Repeated reports
have appeared in the literature stating that muscle contains amylase
besides phosphorylase (104, 105), although the amounts of muscle
amylase in the rat and mouse are very low (see Table II) (44). Amylase has been observed to occur in the kidney, heart, thyroid, and testes
(106). The amounts of amylase in the spleen, heart, kidneys, muscle,
brain, perirenal fat, and colon of the rat, mouse, guinea pig, dog, and
chicken have been tabulated by McGeachin et al. (44) (see Table IV)
and are very low compared to the amounts of pancreatic amylase.