title: Milk glucosidase activity enables suckled pup starch digestion.
abstract: ᅟ: 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.
authors.affiliation: Children's Nutrition Research Center, Baylor College of Medicine and Texas Children's Hospital, Houston, TX, USA. blnjr@sbcglobal.net.
authors.forename: B L
authors.initials: BL
authors.lastname: Nichols
authors.affiliation: Children's Nutrition Research Center, Baylor College of Medicine and Texas Children's Hospital, Houston, TX, USA. marlinda76@hotmail.com.
authors.forename: M
authors.initials: M
authors.lastname: Diaz-Sotomayor
authors.affiliation: Children's Nutrition Research Center, Baylor College of Medicine and Texas Children's Hospital, Houston, TX, USA. seavery@texaschildrens.org.
authors.forename: S E
authors.initials: SE
authors.lastname: Avery
authors.affiliation: Children's Nutrition Research Center, Baylor College of Medicine and Texas Children's Hospital, Houston, TX, USA. schacko@bcm.edu.
authors.forename: S K
authors.initials: SK
authors.lastname: Chacko
authors.affiliation: Children's Nutrition Research Center, Baylor College of Medicine and Texas Children's Hospital, Houston, TX, USA. dhadsell@bcm.edu.
authors.forename: D L
authors.initials: DL
authors.lastname: Hadsell
authors.affiliation: Department of Pediatrics, State University of New York, Buffalo, NY, USA. sbaker@upa.chob.edu.
authors.forename: S S
authors.initials: SS
authors.lastname: Baker
authors.affiliation: Whistler Center for Carbohydrate Research, Purdue University, West Lafayette, IN, USA. hamakerb@purdue.edu.
authors.forename: B R
authors.initials: BR
authors.lastname: Hamaker
authors.affiliation: Whistler Center for Carbohydrate Research, Purdue University, West Lafayette, IN, USA. like.yan.2011@gmail.com.
authors.forename: L K
authors.initials: LK
authors.lastname: Yan
authors.affiliation: Whistler Center for Carbohydrate Research, Purdue University, West Lafayette, IN, USA. amylin@uidaho.edu.|University of Idaho, Moscow, ID, USA. amylin@uidaho.edu.
authors.forename: H M
authors.initials: HM
authors.lastname: Lin
authors.affiliation: Children's Nutrition Research Center, Baylor College of Medicine and Texas Children's Hospital, Houston, TX, USA. rqc@uaslp.mx.|Whistler Center for Carbohydrate Research, Purdue University, West Lafayette, IN, USA. rqc@uaslp.mx.
authors.forename: R
authors.initials: R
authors.lastname: Quezada-Calvillo
keywords: Glucogenesis from 13C-starch; Maltase-glucoamylase; Starch digestion; Suckling; Sucrase-isomaltase; Weaning
references.citation: J Nutr. 2009 Apr;139(4):684-90
references.pmid: 19193815
references.citation: J Proteomics. 2015 Feb 26;116:34-43
references.pmid: 25576853
references.citation: Pediatr Res. 1983 Jan;17(1):15-8
references.pmid: 6188091
references.citation: Biochem J. 1979 Feb 15;178(2):407-13
references.pmid: 109086
references.citation: Pediatr Res. 1986 Aug;20(8):740-3
references.pmid: 3737286
references.citation: J Nutr. 2001 Feb;131(2):409S-20S
references.pmid: 11160571
references.citation: J Pediatr. 2015 Aug;167(2):317-24.e1
references.pmid: 26073105
references.citation: Proc Natl Acad Sci U S A. 2013 Apr 9;110(15):E1380-9
references.pmid: 23520048
references.citation: J Pediatr Gastroenterol Nutr. 2000 May;30(5):494-502
references.pmid: 10817278
references.citation: J Pediatr Gastroenterol Nutr. 2013 Dec;57(6):704-12
references.pmid: 23838818
references.citation: Pediatr Res. 1982 Jun;16(6):470-3
references.pmid: 6179036
references.citation: Arch Dis Child. 1993 Jan;68(1 Spec No):62-5
references.pmid: 7679890
references.citation: Am J Clin Nutr. 2003 Jun;77(6):1537S-1543S
references.pmid: 12812151
references.citation: J Pediatr. 1983 Jul;103(1):23-8
references.pmid: 6408235
references.citation: Pediatrics. 1965 Jun;35:944-54
references.pmid: 14296420
references.citation: Matern Child Nutr. 2008 Apr;4 Suppl 1:24-85
references.pmid: 18289157
references.citation: J Nutr. 2007 Jul;137(7):1725-33
references.pmid: 17585022
references.citation: Mol Nutr Food Res. 2014 May;58(5):1111-21
references.pmid: 24442968
references.citation: J Pediatr Gastroenterol Nutr. 2012 Nov;55 Suppl 2:S43-5
references.pmid: 23103656
references.citation: J Pediatr Gastroenterol Nutr. 1982;1(1):43-8
references.pmid: 6193260
references.citation: J Pediatr. 1989 Dec;115(6):959-68
references.pmid: 2585235
references.citation: Pediatrics. 1985 Jan;75(1 Pt 2):160-6
references.pmid: 2578223
references.citation: J Pediatr Gastroenterol Nutr. 2010 Jan;50(1):92-8
references.pmid: 19543110
references.citation: J Biol Chem. 1998 Jan 30;273(5):3076-81
references.pmid: 9446624