Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.2.1.108 (lactase)
 2,133 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Epidermal growth factor (EGF) has been shown to be present in the milk of several species, including the rat, and to have gastrointestinal effects when given parenterally or orally in pharmacologic doses. We investigated the effect of enteral EGF in physiologic doses on the small intestine and colon of suckling rats. Serum thyroxine (T4) levels were also measured. Rats were gavage-fed by hand with an artificial formula with or without added EGF every 3 h from 11 to 14 days of age. Intake was adjusted to deliver 30 kcal/100 g b.wt./day of formula and 16 micrograms/kg/day of EGF approximating the daily caloric intake, and about twice the estimated daily EGF intake for suckling rats. Weight gain did not differ between groups (fed EGF: 3.8 + 0.2 g; not fed EGF: 3.7 + 0.1 g). The protein content of the whole colon of rats fed an EGF-containing formula was significantly lower and the DNA content significantly higher, than in rats fed formula without added EGF. The protein/DNA ratio was therefore markedly higher in the animals fed formula without added EGF; these effects were most evident in the distal colon. In contrast, there was no effect of EGF on small intestinal protein and DNA content; lactase, sucrase, and maltase activities were likewise unaffected, as was serum T4. These data suggest a physiologic role for breast milk EGF in the development of the suckling rat colon.
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PMID:Effects of enterally fed epidermal growth factor on the small and large intestine of the suckling rat. 349 22

Epidermal growth factor and related substances mediate their effects on epithelial cells through binding to high-affinity receptors (EGF-R) at their basolateral surface and it is hypothesized that this growth factor system play a major role in gut morphogenesis and maintenance. The current review emphasizes on analyzing the expression and the biochemical characteristics of EGF-R in human fetal gut segments and correlating the biological actions of EGF-R ligands. They appear to be primarily involved in the local regulation of epithelial cell proliferation in which EGF-R are abundant. Alternatively, EGF-R ligands exert some precocious maturative effects by increasing intestinal lactase activity and decreasing brush border hydrolases in colon while they down modulate the expression of segment-specific markers of terminal differentiation such as sucrase, trehalase and glucoamylase in the intestine and chief cell lipase in the stomach. Such effects are consistent with the identification of receptors at the surface of all epithelial cell types, illustrating the modulatory role of EGF on differentiated gut epithelial cells. Comparison with animal models illustrates similar biochemical properties of receptors and underlines physiological aspects specific to human gut development. The relevance for ligand heterogeneity is also discussed and tentatively associated with different delivery pathways or physiological responses.
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PMID:Ontogeny of EGF receptors in the human gut. 988 80