Epidermal Growth Factor Receptors during Postnatal Development of the Mouse Colon*

Abstract

The present study was undertaken to establish the postnatal profile of specific epidermal growth factor (EGF) binding in the maturing mouse colon, with particular emphasis on possible regional differences between both proximal and distal colonic binding patterns vs. those of the small intestine. Binding studies using [125I]EGF were performed on isolated epithelial cells obtained from 2-, 5-, 9-, 16-, and 22-day-old mice as well as adults. At 2 days, cells isolated from the entire colon bound 4 times more [125I]EGF than did corresponding intestinal cells, whereas between the ages of 5 days to adult, colonic cells bound between 1.7-2.5 times more labeled EGF than their intestinal counterparts. The immature colon already exhibited maximal binding after birth as opposed to the small intestine where binding only reached maximal values by the third week of life. Comparison between the proximal and distal colon in 9-, 16-, and 22-day-old mice revealed a further 2-fold increase in EGF binding in the distal colon compared to that in the proximal colon. Scatchard plots of [125I]EGF displacement by native EGF in both proximal and distal colonic segments also revealed the presence of two classes of binding sites, with high affinity constants (K1) significantly greater in the distal colon. These results demonstrate for the first time not only the continued presence of EGF receptors in mouse colonic epithelium, but also significant regional differences in EGF-binding capacity within the digestive tract throughout the postnatal period.

Intestinal Expression of TFF and Related Genes During Postnatal Development in a Piglet Probiotic Trial

“…In order to address the functional importance of this observation, further studies are required. The significantly reduced EGFR expression comparing pre-and postweaning time points in porcine ascending colon correlates with a study in mice showing highest EGFR expression immediately after birth in the maturing colon [56].…”

Presence and characteristics of epidermal growth factor receptors in human fetal small intestine and colon

“…The pattern of EGF binding in the fetal human colon is also noteworthy since colonic epithelial cells exhibited even higher EGF binding than their intestinal counterparts. A similar observation was also noted in an earlier study involving EGF receptors during postnatal development of mouse colon [16]. This higher binding in colonic epithelial cells can be attributed partly to a higher concentration of EGF 116 receptors on their cell surface.…”

Growth Retardation, Duodenal Lesions, and Aberrant Ileum Architecture in Triple Null Mice Lacking EGF, Amphiregulin, and TGF-α

“…These results agree closely with previous detection of EGF-R in the rat small intestine by Western blot 38 and in the rodent gut by binding of radiolabeled ligand. 39,40 Interestingly, the ontogeny of EGF-R protein levels in the aaeett small intestine was the mirror image of that in wild-type tissue. Thus, EGF-R protein was consistently detected at day 2 in proximal and especially distal portions of the aaeett small intestine, but then declined thereafter and was generally nondetectable by day 21 (Figure 6).…”