The oligosaccharidases lactase and sucrase-dextrinase undergo dramatic alterations during development of the mammalian small intestine. In order to investigate the mechanisms relating to these dynamic events, the synthesis and membrane-associated assembly of these two enzymes will be studied in the maturing rat. Antibodies monospecific for lactase and sucrase-dextrinase will be used in combination with advanced techniques for intestinal perfusion and isolation of cellular organelles well established in the sponsor's laboratory to investigate molecular level events in the in vivo synthesis and assembly of these enzymes in the normally developing intestine. With these studies as a basis, regulation of the developmental alterations of lactase and sucrase-dextrinase by specific intraluminal carbohydrate substrates will be investigated at the molecular level using the above techniques in combination with a unique experimental model developed by the candidate. This model, in which nutrients adequate for normal growth are intravenously administered to infant animals prior to and during the weaning period, makes possible investigation of specific intraluminally administered nutrients without introduction of artifact due to malnutrition. These studies should generate precise information on regulation of synthesis and assembly of lactase and sucrase-dextrinase in the developing intestine and the mechanisms by which these enzymes are modulated by luminal nutrients during intestinal maturation.

Agency
National Institute of Health (NIH)
Institute
Eunice Kennedy Shriver National Institute of Child Health & Human Development (NICHD)
Type
Clinical Investigator Award (CIA) (K08)
Project #
5K08HD000779-03
Application #
3081333
Study Section
Maternal and Child Health Research Committee (HDMC)
Project Start
1987-08-01
Project End
1990-07-31
Budget Start
1989-08-01
Budget End
1990-07-31
Support Year
3
Fiscal Year
1989
Total Cost
Indirect Cost
Name
Stanford University
Department
Type
Schools of Medicine
DUNS #
800771545
City
Stanford
State
CA
Country
United States
Zip Code
94305
Reisenauer, A M; Castillo, R O (1994) Regulation of the ontogenic and regional expression of intestinal aminooligopeptidase. J Pediatr Gastroenterol Nutr 18:1-8
Liu, T; Reisenauer, A M; Castillo, R O (1992) Ontogeny of intestinal lactase: posttranslational regulation by thyroxine. Am J Physiol 263:G538-43
Castillo, R O; Feng, J J; Stevenson, D K et al. (1992) Maturation of jejunoileal gradients in rat intestine: the role of intraluminal nutrients. Biol Neonate 62:351-62
Tsuboi, K K; Kwong, L K; Sunshine, P et al. (1992) Mechanism of maturational decline of rat intestinal lactase-phlorizin hydrolase. Biochem J 282 ( Pt 1):107-13
Bernstein, D; Bell, J G; Kwong, L et al. (1992) Alterations in postnatal intestinal function during chronic hypoxemia. Pediatr Res 31:234-8
Reisenauer, A M; Lee, E A; Castillo, R O (1992) Ontogeny of membrane and soluble amino-oligopeptidases in rat intestine. Am J Physiol 262:G178-84
Castillo, R O; Feng, J J; Stevenson, D K et al. (1991) Altered maturation of small intestinal function in the absence of intraluminal nutrients: rapid normalization with refeeding. Am J Clin Nutr 53:558-61
Castillo, R O; Glasscock, G F; Noren, K M et al. (1991) Pituitary regulation of postnatal small intestinal ontogeny in the rat: differential regulation of digestive hydrolase maturation by thyroxine and growth hormone. Endocrinology 129:1417-23
Castillo, R O; Kwong, L K; Tsuboi, K K (1991) Synthesis and accumulation of protein and carbohydrases along the rat villus column. J Pediatr Gastroenterol Nutr 13:235-41
Castillo, R O; Reisenauer, A M; Kwong, L K et al. (1990) Intestinal lactase in the neonatal rat. Maturational changes in intracellular processing and brush-border degradation. J Biol Chem 265:15889-93

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