Comparative studies on the serum levels of alpha-1-antitrypsin and alpha-macroglobulin in several mammals

The sera of human, cattle, horse, sheep, goat, pig, dog, rabbit, guinea pig, rat, hamster, and mouse were assayed for total trypsin-inhibiting capacity, and for concentrations of alpha-1-antitrypsin and alpha-macroglobulin. The rodents examined showed striking species differences: the alpha-1-antitrypsin levels of mouse, rat, and guinea pig were more than twice the human level, while the alpha-macroglobulin levels of hamster and guinea pig were 340 and 40%, respectively, of the human level. On the other hand, little variations were found among the large domestic animals, their levels of the two inhibitors being similar to those of the human.