Intestinal arginase in the phylogenetic development of animals

: The activity of intestinal arginase was studied in 31 species belonging to the types Annelides, Arthropoda and Chordata. Large variations of the enzyme activity were tested. The differences were of 2 orders of magnitude--100 times. Four groups were selected: animals with very low arginase activity up to 0.20 microM of ornithine/mg of protein/15 min; this group comprises both phylogenetically lower and higher animals (cockroach, locust, frog, duck, domestic hen, broiler chicken, horse, hyppopotamus, ox, sheep, antelope); animals with rather low activity up to 0.22 to 0.60 microM of ornithine/mg of protein/15 min (crayfish, herring, salmon, bream, cod, pike-perch, mink, fox, dog. man); animals with moderate activity up to 0.63 to 1.15 microM of ornithine/mg of protein/15 min (pigeon, coypu, guinea-pig, hog); animals with high activity up 1.15 to 9.26 microM of ornithine/mg of protein/15 min (rabbit, rat, hamster, mouse). According to the profile the activity of the enzyme along the long axis of the intestine two groups of animals could be separated: one in which arginase activity is the same over the whole length of the intestine, in animals with very low and rather low arginase activity, and the second in which there is a distinct topographical differentiation of activity (the highest in the jejunum decreasing gradually with differing gradients) in animals with moderate and high arginase activity. Intestinal arginase activity in quails in ontogenic development from the birth up to 233 days, show 2 peaks--one at 9 and the second at 23 days.