Intestinal lactase synthesis during postnatal development in the rat

ABSTRACT ABSTRACT: To elucidate the mechanism of the developmental decline in intestinal lactase activity at weaning, we examined lactase synthesis in suckling and adult rats. Lactase was

purified to homogeneity from pooled intestines of newborn rats and used to raise a monospecific antibody. Using this antibody, we developed a quantitative immunoprecipitation assay for

lactase. Intestinal microvillus membrane proteins were labeled in 15-day and adult rats by intraluminal pulse-chase with 3H-leucine, and newly synthesized lactase quantified by

immunoprecipitation. When lactase synthesis was expressed as the quantity of microvillus membrane lactase synthesized relative to total microvillus membrane protein synthesized, a

significantly greater proportion of 3H-leucine incorporation into lactase was demonstrated in the suckling animals. No structural differences between newly synthesized suckling and adult

lactase were observed when they were compared by SDS-polyacrylamide gel electrophoresis and fluorography. These data suggest that a change in the rate of lactase synthesis plays a role in

the postweaning decline in enzyme activity. SIMILAR CONTENT BEING VIEWED BY OTHERS STRUCTURAL AND IMMUNOENDOCRINE REMODELING IN GUT, PANCREAS AND THYMUS IN WEANING RATS FED POWDERED MILK

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AFFILIATIONS * Division of Pediatric Gastroenterology and Nutrition, The Floating Hospital, New England Medical Center, Boston, 02111, Massachusetts Maureen M Jonas, Robert K Montgomery 

& Richard J Grand * Department of Pediatrics, Tufts University School of Medicine, Boston, 02111, Massachusetts Maureen M Jonas, Robert K Montgomery & Richard J Grand Authors *

Maureen M Jonas View author publications You can also search for this author inPubMed Google Scholar * Robert K Montgomery View author publications You can also search for this author

inPubMed Google Scholar * Richard J Grand View author publications You can also search for this author inPubMed Google Scholar RIGHTS AND PERMISSIONS Reprints and permissions ABOUT THIS

ARTICLE CITE THIS ARTICLE Jonas, M., Montgomery, R. & Grand, R. Intestinal Lactase Synthesis during Postnatal Development in the Rat. _Pediatr Res_ 19, 956–962 (1985).

https://doi.org/10.1203/00006450-198509000-00018 Download citation * Received: 12 March 1984 * Accepted: 26 April 1985 * Issue Date: 01 September 1985 * DOI:

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