Gastrointestinal absorption of epidermal growth factor in suckling rats.
Epidermal growth factor (EGF) was detected in the milk of adult lactating Sprague-Dawley female rats (38.85 ng/ml) and in the stomach (37.25 ng/g content) and plasma (32.36 ng/ml) of 13-day-old suckling offspring. Sixty-nanogram (0.12 mCi/ml) doses of 125I-EGF were administered orally to sucklings in 200 microliters of buffer for 0, 0.5, 1.0, and 3.0 h. Lung, liver kidney, brain, and blood each contained 1% or less of the administered radioactivity. Stomach wall (8%) and content (63%), intestinal wall (15%) and flushing (38%), and skin (18%) contained larger amounts reaching maxima in these three regions at 0, 0.5, and 3.0 h, respectively. Except for skin, a substantial amount of radioactivity from all tissues represented intact (6-90%) and immunoreactive (3-90%) EGF based on Sephadex G-25 chromatography and anti-EGF antibody binding, respectively. From 30 to 55% of the radioactivity from wall (gastric or small intestinal) or lumina was also capable of binding to A-431 cell surface receptors. Isoelectric points of major species found in stomach (4.2), intestine (4.1), and other tissues differed from that of administered EGF (4.5).
D000818:Animals; D004815:Epidermal Growth Factor / Q000302:isolation & purification / Q000378:metabolism*; D007408:Intestinal Absorption; D007457:Iodine Radioisotopes; D007700:Kinetics; D008297:Male; D051379:Mice; D008892:Milk / Q000032:analysis; D051381:Rats; D011919:Rats, Inbred Strains; D013363:Submandibular Gland; D014018:Tissue Distribution
D007457:Iodine Radioisotopes; D004815:Epidermal Growth Factor