Abstract
The present studies were designed to examine the regulation of Na+/H+ exchange activity by epidermal growth factor (EGF) in an in vitro system. Na+/H+ exchange activity was determined in brush-border membranes isolated from rat jejunal enterocytes incubated with epidermal growth factor and a number of second messengers. EGF at physiological concentrations stimulated Na+/H+ exchange activity without affecting vesicle size. The stimulation of Na+/H+ activity was the result of increasing V(max) of Na+/H+ (6.0 ± 0.4 compared with 3.3 ± 0.27 nmol/mg protein/5 sec, P < 0.01). K(m) values of the Na+/H+ exchanger in brush-border membrane from cells stimulated with EGF and controls were similar (16.0 ± 3.0 vs 13.0 ± 3.0, respectively). Na+/H+ activity was inhibited by phorbol esters, calmodulin, and cyclic AMP. The effects of EGF, calmodulin, cyclic AMP, and phorbol esters were dependent on ATP, because depleting the cells from ATP masked the effects on Na+/H+ exchange activity. The results suggest that EGF stimulates Na+/H+ exchange activity in the enterocytes. This stimulation is most likely not via activation of the phosphatidylinositol pathway.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 289-295 |
| Number of pages | 7 |
| Journal | Proceedings of the Society for Experimental Biology and Medicine |
| Volume | 201 |
| Issue number | 3 |
| State | Published - 1992 |
| Externally published | Yes |
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ASJC Scopus subject areas
- Biochemistry, Genetics and Molecular Biology(all)
Cite this
Epidermal growth factor up-regulates intestinal Na+/H+ exchange activity. / Ghishan, Fayez K; Kikuchi, K.; Riedel, B.
In: Proceedings of the Society for Experimental Biology and Medicine, Vol. 201, No. 3, 1992, p. 289-295.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Epidermal growth factor up-regulates intestinal Na+/H+ exchange activity
AU - Ghishan, Fayez K
AU - Kikuchi, K.
AU - Riedel, B.
PY - 1992
Y1 - 1992
N2 - The present studies were designed to examine the regulation of Na+/H+ exchange activity by epidermal growth factor (EGF) in an in vitro system. Na+/H+ exchange activity was determined in brush-border membranes isolated from rat jejunal enterocytes incubated with epidermal growth factor and a number of second messengers. EGF at physiological concentrations stimulated Na+/H+ exchange activity without affecting vesicle size. The stimulation of Na+/H+ activity was the result of increasing V(max) of Na+/H+ (6.0 ± 0.4 compared with 3.3 ± 0.27 nmol/mg protein/5 sec, P < 0.01). K(m) values of the Na+/H+ exchanger in brush-border membrane from cells stimulated with EGF and controls were similar (16.0 ± 3.0 vs 13.0 ± 3.0, respectively). Na+/H+ activity was inhibited by phorbol esters, calmodulin, and cyclic AMP. The effects of EGF, calmodulin, cyclic AMP, and phorbol esters were dependent on ATP, because depleting the cells from ATP masked the effects on Na+/H+ exchange activity. The results suggest that EGF stimulates Na+/H+ exchange activity in the enterocytes. This stimulation is most likely not via activation of the phosphatidylinositol pathway.
AB - The present studies were designed to examine the regulation of Na+/H+ exchange activity by epidermal growth factor (EGF) in an in vitro system. Na+/H+ exchange activity was determined in brush-border membranes isolated from rat jejunal enterocytes incubated with epidermal growth factor and a number of second messengers. EGF at physiological concentrations stimulated Na+/H+ exchange activity without affecting vesicle size. The stimulation of Na+/H+ activity was the result of increasing V(max) of Na+/H+ (6.0 ± 0.4 compared with 3.3 ± 0.27 nmol/mg protein/5 sec, P < 0.01). K(m) values of the Na+/H+ exchanger in brush-border membrane from cells stimulated with EGF and controls were similar (16.0 ± 3.0 vs 13.0 ± 3.0, respectively). Na+/H+ activity was inhibited by phorbol esters, calmodulin, and cyclic AMP. The effects of EGF, calmodulin, cyclic AMP, and phorbol esters were dependent on ATP, because depleting the cells from ATP masked the effects on Na+/H+ exchange activity. The results suggest that EGF stimulates Na+/H+ exchange activity in the enterocytes. This stimulation is most likely not via activation of the phosphatidylinositol pathway.
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UR - http://www.scopus.com/inward/citedby.url?scp=0026469976&partnerID=8YFLogxK
M3 - Article
C2 - 1332072
AN - SCOPUS:0026469976
VL - 201
SP - 289
EP - 295
JO - Proceedings of the Society for Experimental Biology and Medicine. Society for Experimental Biology and Medicine (New York, N. Y.)
JF - Proceedings of the Society for Experimental Biology and Medicine. Society for Experimental Biology and Medicine (New York, N. Y.)
SN - 0037-9727
IS - 3
ER -