Pre- and Post-hatching Development of the ALP-ase Activity in the Small Intestine of the Chick and Quail. : I. Biochemical Evaluation.

In order to correlate the biochemical determination of the phosphatase activity to its histochemical and cytochemical localization the alkaline phosphatase activity in the small intestine of pre and post hatch chick and quail was estimated by colorimetry. Using phenylphosphate as substrate the supernatant of homogenate of three segments, duodenum, jejunum and ileum from each group of embryo or chick was incubated for 15 min. at lit and optical density was read in a Klett -Summerson spectrophotometer. The result obtained was then transformed into King-Armstrong units. At pre-hatching stages the ALP-ase activity in every semgents of intestine was considerably lower than that had been implied by histochemical works. It was estimated that the activity detectable by histochemical studies using /3 glycerophosphate as substrate might be comparable to those higher than 10 King-Armstrong unit in this study. Actually the activity until one or two days before hatch remainded lower than 10 units. The ALP ase activity then drastically increased during the period from the last day of the incubation to the first or second day of the post-hatch life. When maximum activity was attained it ranged from 115 to 160 in the duodenum, 65 to 100 in the jejunum and 35 to 45 in the ileum. Shortly after this upserge the ALP-ase activity sharply fell to the level of that of two months old chick. The average activity from the duodenum, jejunum, and ileum of the two months old chicks was 87ｱ10, 42ｱ 4 , and 8 ｱ 3 , respectively. A proximodistal gradient of the ALP-ase activity in the small intestine was suggested by the highest activity in the duodenum, the moderate one in the jejunum and the least in the ileum. (Received June 30, 1974)