title: Role of vitamin A in modulating the radiation-induced changes in intestinal disaccharidases of rats exposed to multifractionated gamma-radiations.
abstract: OBJECTIVE
  The aim of this investigation was to determine whether pre- or post-administration of vitamin A will be effective in reducing the radiation-induced alterations in intestinal disaccharidases in rats.
  
  
  METHODS
  Rats were subjected to fractionated whole-body irradiation (20 x 0.5 Gy). Intestinal lactase activity as well as maltase and sucrase activities were assessed. Vitamin A was administered at daily intraperitoneal dose of 15,000 IU/kg body weight for 7 days prior to radiotherapy and thereafter twice weekly throughout therapy up to 7 days post irradiation.
  
  
  RESULTS
  In irradiated rats a marked decrease in intestinal lactase activity to about one-fourth of those in non-irradiated rats was observed. In addition, a significant reduction in maltase and sucrase activities to one half of the control group was observed. The application of vitamin A significantly improved the radiation-induced inhibition of intestinal enzymes. Pretreatment application of vitamin A is more efficient to protect against radiation injury than a posttreatment application.
  
  
  CONCLUSIONS
  The usage of vitamin A for modulation of radiation-induced changes in intestinal enzymes provides sufficient protection against treatment side effects induced by large volume radiotherapy.
authors.affiliation: Department of Biochemistry, Faculty of Pharmacy, Cairo University, Egypt.
authors.forename: A A
authors.initials: AA
authors.lastname: Shaheen
authors.forename: S H
authors.initials: SH
authors.lastname: Hassan
mesh_terms: D000818:Animals; D004186:Disaccharidases / Q000187:drug effects / Q000528:radiation effects*; D005720:Gamma Rays; D007274:Injections, Intraperitoneal; D007422:Intestines / Q000187:drug effects / Q000201:enzymology* / Q000528:radiation effects; D007583:Jejunum / Q000201:enzymology / Q000528:radiation effects; D043322:Lactase; D008297:Male; D011829:Radiation Dosage; D051381:Rats; D017208:Rats, Wistar; D013393:Sucrase / Q000378:metabolism / Q000528:radiation effects; D014801:Vitamin A / Q000008:administration & dosage / Q000494:pharmacology*; D014916:Whole-Body Irradiation; D000520:alpha-Glucosidases / Q000378:metabolism / Q000528:radiation effects; D001616:beta-Galactosidase / Q000378:metabolism / Q000528:radiation effects
chemical_list: D014801:Vitamin A; D004186:Disaccharidases; D043322:Lactase; D000520:alpha-Glucosidases; D001616:beta-Galactosidase; D013393:Sucrase