Abstract
During the development of intestinal cells, energy is required for a number of functions: maintenance of cellular proliferation/ differentiation and migration/ and absorption and packaging of absorbed material. While glutamine is the major fuel source for the entire small intestine, the utilization of glutamine during the development of the intestinal cell has not been described. We have examined the regulation of glutaminase (EC 3.5.1.2), the entry enzyme for glutamine metabolism/ in enterocytes isolated along the villus-crypt axis from jejunum. Specific activity of glutaminase, μmol/mg protein/h, was 5.07±0.60 in villus cells (0-75% of the total protein removed from jejunum)/ 6.07±1.29 in the villus crypt junction cells (75-95% of total protein) and 3.91 ± 0.80 in crypt cells (95-100% of total protein). Quantity of glutaminase protein was determined by a dot immunobinding assay using an antibody to purified glutaminase. Immunoreactive glutaminase-protein relative to total cell protein was 6.03 ± 1.99 cpm/ μg homogenate protein in villus cells, 3.34±1.16 cpm/μg at the villus-crypt junction and 4.47±1.94 in crypt cells. Thus activity of glutaminase relative to immunoreactive protein was 2.2-fold higher at the villus crypt junction than in villus. All cell types in jejunum have significant activity of glutaminase. The highest activity, present in the area of rapid cellular differentiation, is due to an increased activation of enzyme protein.
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Nagy, L., Kretchmer, N. 704 DEVELOPMENT OF GLUTAMINASE ALONG THE VILLUS-CRYPT AXIS OF RAT JEJUNUM. Pediatr Res 19, 228 (1985). https://doi.org/10.1203/00006450-198504000-00734
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DOI: https://doi.org/10.1203/00006450-198504000-00734