| Abstrakt: |
Intestinal transmission of macromolecules occurs during the neonatal period for many species, but ceases (intestinal closure) in the rat at weaning, while already within 24-36 h after birth in the suckled pig. After closure, a small residual transmission of macromolecules to the blood is seen, which increases with decreasing Mw. The nonapeptide (Deamino-cysteine D-arginine) vasopressin, DDAVP (Mw = 1007 Da) was gavage-fed to pre- and post-closure and pre- and post-weaning rats and piglets. The blood serum concentration of DDAVP was used as a measure of the intestinal transmission and was determined with RIA after 0.5, 1, 2 and 4 h.Significantly higher serum levels were found both in preclosure pigs (newborn, unsuckled) and rats (14 days old) as compared to postclosure pigs (36 h old) and rats (30 d old and weaned). In the piglet, the postclosure serum level was constant until weaning (32 days), when a marked decrease in the DDAVP level occurred after 4 days. However, the DDAVP concentration returned to the preweaning levels at 60 days of age. The results indicate that DDAVP might be a useful marker, since it behaves as a macro-molecule around closure. In addition, DDAVP can be used to monitor intestinal permeability changes at weaning, where traditional macromolecules like BSA are of limited usefulness. |
