AJP - Gastrointestinal and Liver Physiology, Vol 266, Issue 5 935-G939, Copyright © 1994 by American Physiological Society
Absorption of platelet-activating factor acetylhydrolase by rat intestine
M. Furukawa, R. A. Frenkel and J. M. Johnston
Department of Biochemistry, Cecil H. & Ida Green Center for Reproductive Biology Sciences, University of Texas Southwestern Medical Center, Dallas 75235.
Platelet-activating factor acetylhydrolase (PAF-AH) is a 43-kDa protein
that catalyzes the degradation and inactivation of this potent phospholipid
mediator. PAF plays an important role in the pathogenesis of necrotizing
enterocolitis (NEC), and the elevation of the plasma PAF-AH activity may be
beneficial in the prevention of this disease. The activity of PAF-AH was
transferred from the mucosal to the serosal fluid in intestinal sacs from
neonatal rats. Translocation was highest on day 15, decreased by day 21,
and disappeared by day 24. Greater transport of the enzyme was noted in the
neonatal jejunum compared with duodenum or ileum. PAF-AH absorption in
15-day-old rats was decreased by the addition of inhibitors of energy
production and by low temperature. We have, therefore, concluded that the
enzyme transport is an energy-dependent process. It is suggested that
PAF-AH found in milk may prove to be beneficial in the prevention of NEC by
its translocation across the intestinal mucosa. The absorption of
macromolecules in the neonate, in addition to providing a passive immunity,
may also serve a protective role by inactivating certain proinflammatory
agents, such as PAF.
