Milk glucosidase activity enables suckled pup starch digestion.
Mol Cell Pediatr
; 3(1): 4, 2016 Dec.
Article
in En
| MEDLINE
| ID: mdl-26830109
ABSTRACT
UNLABELLED á
Starch requires six enzymes for digestion to free glucose two amylases (salivary and pancreatic) and four mucosal maltase activities; sucrase-isomaltase and maltase-glucoamylase. All are deficient in suckling rodents. OBJECTIVE:
The objective of this study is to test (13)C-starch digestion before weaning by measuring enrichment of blood (13)C-glucose in maltase-glucoamylase-null and wild-type mice.METHODS:
Maltase-glucoamylase gene was ablated at the N-terminal. Dams were fed low (13)C-diet and litters kept on low (13)C-diet. Pups were weaned at 21 days. Digestion was tested at 13 and 25 days by intragastric feeding of amylase predigested (13)C-α-limit dextrins. Blood (13)C-glucose enrichment was measured by gas chromatography combustion isotope ratio mass spectrometry (GCRMS) using penta-acetate derivatives.RESULTS:
Four hours after feeding, blood (13)C-glucose was enriched by 26 × 10(3) in null and 18 × 10(3) in wild-type mice at 13 days and 0.3 × 10(3) and 0.2 × 103 at 25 days (vs. fasting p = 0.045 and p = 0.045). By jejunal enzyme assay, immunohistochemistry, or Western blots, there was no maltase activity or brush border staining with maltase-glucoamylase antibodies at 13 days, but these were fully developed in the wild-type mice by 25 days. In 13-day null mice, luminal contents were stained by maltase-glucoamylase antibodies. Lactating the mammary gland revealed maltase-glucoamylase antibody staining of alveolar cells. Reverse transcription/polymerase chain reaction (RT/PCR) of lactating glands revealed a secreted form of maltase-glucoamylase.CONCLUSIONS:
(1) (13)C-α-limit dextrins were rapidly digested to (13)C-glucose in 13-day mice independent of maltase-glucoamylase genotype or mucosal maltase activity. (2) This experiment demonstrates that a soluble maltase activity is secreted in mouse mother's milk which enables suckling pup starch digestion well before brush border enzyme development. (3) This experiment with (13)C-α-limit dextrins needs to be repeated in human breast fed infants.
Full text:
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Collection:
01-internacional
Database:
MEDLINE
Language:
En
Journal:
Mol Cell Pediatr
Year:
2016
Document type:
Article
Affiliation country:
Estados Unidos