AJP - Gastrointestinal and Liver Physiology, Vol 269, Issue 6 867-G873, Copyright © 1995 by American Physiological Society
Absorption of epidermal growth factor occurs through the gastrointestinal tract and oral cavity in adult rats
K. R. Purushotham, K. Offenmuller, A. T. Bui, T. Zelles, J. Blazsek, G. S. Schultz and M. G. Humphreys-Beher
Department of Oral Biology, University of Florida, Gainesville 32610, USA.
Introduction of radiolabeled epidermal growth factor (125I-EGF) by gavage
or sublingual confinement resulted in a time-dependent uptake and systemic
organ dissemination in the adult rat. Intact EGF was recovered primarily
from the tongue, parotid, and sublingual/submandibular glands after
administration by sublingual lozenge, whereas gastrointestinal
administration resulted in 125I-EGF recovery primarily from plasma,
stomach, and lung. Recovered radiolabeled EGF retained the ability to bind
to the EGF receptor. Sialoadenectomy caused an increase in 125I-EGF in most
tissues by both routes of administration. Thus, in the adult rat, at least
two pathways exist for the uptake and distribution for salivary
gland-derived EGF present in saliva. With further analyses, sublingual
absorbance of EGF may therefore provide a potential delivery route for
therapeutic use of growth factor, which avoids the hepatic destruction of
EGF after oral administration.
