@entity4663 and biosynthetic enzymes in the @entity35 intestinal mucosa and the influence of XXXX .

@entity137 @entity706 @entity35 @entity8037 @entity7222 @entity7224 @entity2665 @entity7726 @entity4663 @entity4664 @entity11667
The use of @entity2665 ( @entity2665 ) in the clinical treatment of myeloid and @entity706 has been limited by severe host @entity137 to renewing tissues, particularly the intestinal mucosa. Since the drug is a potent inhibitor of @entity11667 biosynthesis, the distributions of @entity7222 and @entity7726 decarboxylases and @entity4664 pools have been characterized in the @entity35 intestinal mucosa in an attempt to discern the basis for MGBG @entity137 . A method of epithelial cell isolation in which fractions of cells are sequentially collected in a villus tip-to-crypt gradient was used. @entity7222 decarboxylase activity was highest in the villus tip region and unexpectedly lowest in the crypts, while @entity7726 decarboxylase activity showed the opposite pattern. Intracellular @entity4664 pools were uniform along the gradient corresponding to the villus length and increased appreciably in the crypt region. The relative concentrations of the individual @entity4663 were highest in the crypts, with @entity11667 and @entity8037 being nearly equivalent in all regions. Twenty-four hr after a single i.p. injection of MGBG (50 mg/kg), @entity7726 decarboxylase activity increased markedly, especially in the crypt region (approximately 50-fold), while @entity7222 decarboxylase activity also increased but to a lesser extent. @entity7224 pools were most affected by MGBG and were elevated 5- to 6-fold, especially in the crypt region. The results are consistent with an alteration of @entity4664 biosynthesis by MGBG being involved in the antiproliferative @entity137 of the drug.
