Development of Gastrointestinal Mucosal Barrier. I. The Effect of Age on Intestinal Permeability to Macromolecules

Abstract

Increased quantities of antigen may penetrate the intestinal mucosa and enter the systemic circulation during the newborn period compared to adult life. No direct measurement of macromolecular transport was reported as a function of perinatal age. One hundred mg of [3H] bovine serum albumin was administered by gavage to rabbits at birth, 1 wk, 2 wk, 6 wk and 1 yr of age; and plasma radioactivity was measured 4 hr after gavage. Plasma concentration of trichloroacetic acid insoluble radioactivity and immunoreactive BSA radioactivity decreased significantly after 1 wk of age. When adult animals were gavaged with the same amount of [3H]BSA/body weight as the 1 wk old animals, they failed to transport as much of the antigen as the younger animals. The intestinal mucosal barrier of newborns may be incompletely developed at birth and allow increased intestinal transport of antigens into the circulation.