Processing of epidermal growth factor by suckling and adult rat intestinal cells
Preparations of intestinal villus and crypt cells were isolated from jejunal segments of suckling (14-day-old) and adult (6- to 7-wk-old) rats. These cell preparations were incubated with /sup 125/I-labeled epidermal growth factor (EGF) at 37/sup 0/C to determine the extent of cellular processing of /sup 125/I-EGF in vitro. /sup 125/I-EGF bound specifically to both crypt and villus cells of suckling rats and was internalized and degraded to similar extents in both cell preparations. Analysis of the /sup 125/I radioactivity in the medium and cellular extract by gel filtration on Sephadex G-25 columns demonstrated the presence of (/sup 125/I)iodotyrosine (24-31%) following 30 min of incubation. This degradation of EGF was accompanied by a loss in the capacity to bind to anti-EGF antibodies (34-52%) and A431 cells (28-48%). Binding, internalization, and processing of /sup 125/I-EGF by crypt cell preparations of adult rats was similar to that of suckling rats. In contrast, little degradation of /sup 125/I-EGF to iodotyrosine and loss of cell binding capability occurred following incubation with adult villus cells. However, a considerable loss in binding to anti-EGF antibody was detected (48%). The results indicate that isolated intestinal cells are capable of degrading /sup 125/I-EGF in vitro in a manner similar to that seen after oral feeding in vivo. They also indicate differences in the processing of /sup 125/I-EGF by isolated villus cells of adult compared with suckling rat.
- Research Organization:
- Univ. of Arizona College of Medicine, Tucson
- OSTI ID:
- 6829559
- Journal Information:
- Am. J. Physiol.; (United States), Vol. 250:6
- Country of Publication:
- United States
- Language:
- English
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551001* - Physiological Systems- Tracer Techniques