Size and proteolytic enzyme activity of the pancreas of several species of vertebrate animals

Pancreas size and trypsin and chymotrypsin activities were determined for cattle, sheep, rats, mice, and chickens of various ages. Pancreas size per kilogram of live body weight was greater for the nonruminants than for the ruminants. Pancreas trypsin activity per milligram of pancreas dry matter was greater for ruminants than for nonruminants; however, activity per kilogram of body weight was greater for rats and mice than for chickens, which in turn was greater than for ruminants. Chymotrypsin activity was greater for rats and mice than for ruminants on the basis of both pancreas dry matter and body weight. In cattle, chymotrypsin activity per unit of pancreas dry matter was highest in the newborn calf, dropped to one-half that level within 1 week after birth, and then increased only slightly with age up to 1 year. The ratios of chymotrypsin to trypsin activities in the pancreas ranged from 0.39 to 1.20 in the ruminants, except for the newborn calf (1.60), and were greater than 2.0 for the other species...