Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: KEGG:D03348 (Lactase)
 283 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The small intestinal mucosa of the neonatal rat expresses primarily lactase activity until just prior to weaning when lactase falls to low levels and a full complement of adult digestive enzymes appears. Insulin-like growth factor 1 (IGF-I) is a normal component of maternal milk of humans and experimental animals. Experiments were performed to examine the concentrations of IGF-I in dam milk and the gastric content of suckling pups. Lactase activity in 1-day-old neonates was 0.66 micromol glucose formed/mg protein/hr (unit) and fell progressively until day 25, whereas sucrase activity at day 1 postpartum was 0.07 units and rose progressively to 0.21 units at day 25. The IGF-I content of dam milk was measured at 1, 5, 10, 15, 18, and 20 days postpartum by radioreceptor assay (RRA). Milk contained 1.02 pmol IGF-I/ml milk at one day postpartum, peaked at day 18 with 5.08 pmol IGF-I/ml, and fell to 2.31 pmol/ml at day 20. By day 25, dams were dry. The IGF-I content of the neonate gastric lumen was also measured by RRA. At day 1 the gastric lumen contained 2.63 pmol IGF-I/ml of luminal contents, fell to 1.06 pmol IGF-I/ml at day 5, and then rose again to peak at 3.37 pmol/ml at day 15 just prior to weaning. Two days after weaning, the level of luminal IGF-I had fallen to 1.15 pmol/ml. These data demonstrate the concentration of IGF-I in maternal milk is reflected in the concentration of the peptide in gastric contents of suckling pups and that the concentration in the gastric lumen may be high enough to affect epithelial cell proliferation and differentiation.
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PMID:Insulin-like growth factor I in suckling rat gastric contents. 868 16

The effect of orally administered IGF-I on intestinal development was assessed in piglets. Cesarean-derived, colostrum-deprived piglets received formula alone or formula containing 65 nM (500 microg/L) of recombinant human IGF-I. IGF-I intake averaged 200 microg/kg/d. On d 7 and 14 postpartum, piglets were killed, organs were removed and weighed, and tissue and blood samples were collected. The small intestine was divided into 13 segments that were weighed and measured. A sample of each segment was fixed in formalin, and the mucosa was scraped for enzyme analyses. Food intake, body and organ weights, intestinal weight, length, protein, DNA and RNA content did not differ between the treatment groups. Serum IGF-I, IGF-II, and IGF-binding protein profiles and tissue IGF-binding protein mRNA expression were also comparable between the treatment groups. In contrast, intestinal enzymes and villus height were increased by oral IGF-I. Lactase was approximately 2-fold higher (p < or = 0.05) in the jejunum and proximal ileum, and sucrase was approximately 50% higher (p < or = 0.05) in the jejunum of IGF-I-treated animals than in controls. Villus height in the terminal ileum was approximately 50% greater in IGF-I-treated animals than in controls (p = 0.03). In conclusion, orally administered IGF-I at 200 microg/kg did not affect whole body or organ growth or serum IGF-I concentrations; however, intestinal disaccharidase activity and ileal villus growth were responsive to orally administered IGF-I, supporting a potential role for milk-borne IGF-I in neonatal intestinal development.
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PMID:Small intestinal disaccharidase activity and ileal villus height are increased in piglets consuming formula containing recombinant human insulin-like growth factor-I. 921 41

Insulin-like growth factors-1 and -2, IGFBP-2 and -3, and receptors for IGF type-1 and type-2 (IGF-1R, IGF-2R), growth hormone (GHR), and insulin (InsR) in neonatal calves are variably expressed among gastrointestinal sites and thought to exert site-specific physiological functions. We studied by real-time reverse-transcription PCR, whether there are differences in the abundance of mRNA coding for IGF-I, IGF-2, IGFBP-2, IGFBP-3, IGF-1R, IGF-2R, GHR, and InsR in compartmentalized layers (fractions) of jejunum and ileum of 5-d-old calves fed colostrum. Samples of jejunum consisted primarily of villi and crypts; samples from ileum consisted mainly of villus tips, crypts, and lamina propria (LP; containing mainly Peyer's patches). After slaughter, segments of middle areas of jejunum and ileum were flushed with 154 mM NaCl. Pieces (5 mm x 5 mm) of jejunal (n = 9) and ileal walls (n = 5) were placed on glass slides and snap-frozen in liquid N before being cut horizontally into 10-mum-deep slices using a cryotome at -20 degrees C. Fifteen consecutive and morphologically similar slices were collected as fractions of villus, crypt, and LP layers, respectively. Fractions were characterized by use of 5'-bromo-2-deoxyuridine (BrdU) that labeled proliferating cells, and by expression of lactase mRNA. The BrdU-labeled cells were present in crypts and LP, but not in tips of villi. Lactase mRNA levels were greater in villus than crypt fractions, but lactase mRNA was absent in LP. In jejunum, mRNA levels, relative to levels of housekeeping genes (sum of levels of mRNA coding for ubiquitin, glyceraldehyde phosphate dehydrogenase, beta-actin, and ribosomal RNA), differed (P < 0.05) between fractions for InsR (crypts > villi), IGFBP-2 (crypts > villi), and IGFBP-3 (crypts > villi), and total RNA levels were greater (P < 0.05) in crypt than villus fractions. In ileum, mRNA levels, expressed relative to housekeeping genes, differed (P < 0.05) between fractions for IGF-I (LP > villi, crypts), IGF-2, and IGFBP-3 (villi > crypts, LP), GHR and InsR (crypts > LP), IGFBP-2 (crypts > villi, LP), and total RNA levels were greater (P < 0.05) in LP and crypt than in villus fractions. In conclusion, the tested fractionation technique is quite applicable for gene expression studies in the intestine of calves. Members of the somatotropic axis and of the insulin receptor are not equally expressed in different jejunal and ileal layers of neonatal calves.
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PMID:Abundance of mRNA encoding for components of the somatotropic axis and insulin receptor in different layers of the jejunum and ileum of neonatal calves. 1554 64