Processing and transfer of epidermal growth factor in developing rat jejunum and ileum.
Using everted sac technique we demonstrated the transfer of 125I-mEGF across the jejunal and ileal walls of suckling, weanling and adult rats. The transfer by the suckling rat jejunum and ileum was significantly inhibited by the presence of dinitrophenol and sodium azide or by the replacement of sodium with potassium or choline, RP-HPLC analysis detected carboxy-terminal processing of 125I-mEGF in suckling and adult rat jejunum and ileum. Suckling rat jejunum produced 125I-des(53)mEGF and 125I-des(49-53)mEGF, whereas 125I-des(48-53)mEGF was detected in suckling rat ileum or adult rat jejunum and ileum. All three forms of 125I-mEGF bound to anti-EGF antibody and EGF receptors. The receptor binding of 125I-des(53)mEGF was higher than that of 125I-mEGF, but those of 125I-des(49-53)mEGF and 125I-des(48-53)mEGF were greatly diminished. Results indicate a carboxy-terminal processing of mouse EGF during uptake and transfer in the small intestine of developing and adult rats, and the resulting products showed altered receptor binding. An identical amino acid sequence of the C-terminal pentapeptide of eGF from mouse, human and possibly rat may suggest a biological significance of C-terminal processing of EGF in the small intestine.
Rao
R K
RK
Department of Pediatrics, University of Arizona College of Medicine, Tucson 85724.
Koldovský
O
O
Korc
M
M
Pollack
P F
PF
Wright
S
S
Davis
T P
TP
D000818:Animals; D000833:Animals, Suckling; D001692:Biological Transport / Q000502:physiology; D002851:Chromatography, High Pressure Liquid; D004815:Epidermal Growth Factor / Q000378:metabolism*; D066246:ErbB Receptors / Q000378:metabolism; D007082:Ileum / Q000254:growth & development / Q000378:metabolism*; D066298:In Vitro Techniques; D007408:Intestinal Absorption; D007457:Iodine Radioisotopes; D007583:Jejunum / Q000254:growth & development / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains
D007457:Iodine Radioisotopes; D004815:Epidermal Growth Factor; D066246:ErbB Receptors