ELSEVIER Mutation Research 370 (1996) 121-126 Genetic Toxicology Effects of the amino acid glutamine on frequency of chromosomal aberrations induced by gamma radiation in Wistar rats Denise Crispim Tavares a, Catarina S. Takahashi a3b7 * a Depto. Gene’tica, Fat. Med. de RibeirZio Preto-USP, Au. Bandeirantes 3900, 14049.900 Ribeiriio Preto, SP, Brazil b Depto. Biologia, Fat. Fil. Cihcias e LRtras de Ribeiriio Preto-USP, Au. Bandeirantes 3900, 14049.901 Ribeiriio Preto, SP, Brazil Received 7 February 1996; revised 25 April 1996; accepted 16 May 1996 Abstract The radiotherapy treatment of human cancer is often limited by the side effects and complications induced in normal surrounding tissues. The use of therapeutic strategies that could protect normal tissues while permitting the death of malignant neoplasm would be advantageous.Some studieshave suggested that the amino acid glutamine (GLN) can serveas a conditionally essentialnutrient in patients in a catabolic condition. The objective of this study was to evaluate the possible radioprotection of GLN on the frequency of chromosomal aberrations, number of metaphases with chromosomal aberrations and mitotic index in bone marrow cells of Runus nontegicus. In this in vivo test system, GLN was administered by gavage at concentrations of 300 and 600 mg/kg body weight, in acute treatments, 30 min or 24 h before exposure to 3 Gy of whole-body gamma radiation. The results obtained in these experiments showed that GLN did not alter significantly the frequency of chromosome aberrations induced by gamma radiation under the experimental conditions used in the present study. Keywords: Glutamine; Ionizing radiation; Chromosomal aberration; Bone marrow cell 1. Introduction The amino acid glutamine (GLN) provides nitro- gen for a number of biosynthetic pathways, serving as a precursor of the purine and pyrimidine rings of nucleic acids and nucleotides such as adenosine triphosphate (ATP) [l]. GLN is avidly consumed by cells in rapid division such as malignant cells [2], fibroblasts [3], enterocytes [4], lymphocytes [5] and * Corresponding author. Tel.: 00.55.16.633-3035. Ext. 309. Fax: 00.55.16.633-5015. E-mail: dtavares@spider.usp.br reticulocytes [6]. Thus, GLN is essential for cell proliferation [7]. The rapid consumption of GLN by these cells in division may be significant in certain patients with gastrointestinal disorders, healing of large wounds, advanced malignant disease, renal failure and/or severe infection [8]. Many of the side effects caused by irradiation are demonstrated to have gastrointestinal nature and they may become serious aggravating the complications observed during radiotherapy. Studies on animals have shown that supplementation with GLN before or after irradiation reduces some of the side effects associated with the gastrointestinal tract, increases 0165-1218/96/$15.00 Copyright 0 1996 Elsevier Science B.V. All rights reserved. PI1 SOl65-1218(96)00067-S