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)

Regulatory roles and a signaling receptor have been proposed for the milk protein lactoferrin (Lf), but none has been definitively characterized. Nichols and colleagues (1987) observed that human lactoferrin (hLf) stimulated thymidine incorporation into the DNA of rat intestinal crypt cells. We tested the hypothesis that chronic Lf administration stimulates intestinal growth by studying neonatal mice suckling transgenic dams secreting about 12 mg/mL hLf in their milk. Specifically, nontransgenic litters were adjusted to eight pups each and cross-fostered to transgenic dams. Controls were pups suckling nontransgenic dams of the same strain. On day 10 postpartum pups were weighed, sacrificed, and the small intestines were weighed, measured, and stored for later determination of enzyme activities. The results indicate that intestinal growth was increased in neonates suckling transgenic dams. The weight of the small intestine was increased about 27% when the pups received milk containing hLf. Intestinal length only increased about 6.5% suggesting that Lf in milk enhanced mucosal growth. The ratio of maltase to lactase in the duodenal segment of the small intestine, an indicator of maturation, was also significantly increased in the pups suckling transgenic milks. Our results imply that chronic oral consumption of human Lf promotes the growth and maturation of the intestinal mucosa, and suggest a possible therapeutic role for the agent in premature infants as well as in patients with bowel damage.
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PMID:Human lactoferrin in the milk of transgenic mice increases intestinal growth in ten-day-old suckling neonates. 1178 71

Human milk stimulates intestinal development through the effects of various moieties. Lactoferrin (LF) is a glycoprotein of human milk whose concentration is highest in colostrum decreasing in mature milk. LF promotes enterocyte growth in intestinal cell lines. We tested the hypothesis that LF induces a distinct effect on enterocyte proliferation and differentiation, depending on its concentration. We examined the dose-related effects by human-native LF (N-LF) in Caco-2 (human colon adenocarcinoma) cells. At high concentrations, N-LF stimulated cell proliferation in immature Caco-2 cells, as judged by 3H-thymidine incorporation. In contrast, sucrase and lactase activities were increased at low but not high LF concentrations and their mRNA were also increased, indicating a transcriptional effect. Because iron binds specific LF sites, we compared the potency of N-LF and iron-saturated LF (I-LF) and found the native form more potent. Finally, we tested the effects by bovine LF (bLF) in the same system and found the latter more potent than the human isoform in inducing cell growth and lactase expression. These results suggest that LF directly induces enterocyte growth and proliferation, depending on its concentration, thereby regulating the earlyx postnatal intestinal development. bLF could be added to infant formula as a growth factor in selected intestinal diseases.
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PMID:Lactoferrin induces concentration-dependent functional modulation of intestinal proliferation and differentiation. 1751 63