Functional development of active sugar transport in the chick intestine

The intestinal sugar transport function of late embryos and young chicks was studied by means of the tissue-accumulation method. Penetration of intestinal slices by sorbose was minimal in all age groups, ranging between 0.2 and 6.0 µmoles/g dry wt. The ratio of sorbose concentration in tissue water to that in the final medium (T/M) never exceeded 0.3. Galactose uptake by embryonic intestine was comparable to that for sorbose. In contrast, 0-day-old slices accumulated 29 µmoles galactose/g dry wt. which gave a T/M of 3.7. Maximal concentrative power was exhibited by 2-day-old slices which accumulated 38 µmoles galactose/g dry wt., resulting in a T/M of 7.4. Mutual inhibition of active transport between glucose and galactose was observed in 2-day-old slices. In intact chicks alimentary absorption rates of these two sugars rose sharply and to about the same extent between 0 and 2 days of age. Hence both in vitro and in vivo evidence suggests that an active transport process for sugars becomes functional in the chick intestine during the hatching period.