Effects of l-arginine-enriched total enteral nutrition on body weight gain, tumor growth, and in vivo concentrations of blood and tissue metabolites in rats inoculated with Walker tumor in the kidney

• Published in: Nutrition (Burbank, Los Angeles County, Calif.) Los Angeles County, Calif.), 2004-02, Vol.20 (2), p.225-229
• Main Authors: Gonzaga Silva, Lúcio Flávio, Odorico de Moraes, Manoel, Santos Dias Soares, Felipe, Mota Moura Fé, Daniel, Cavalcante, João Luiz B.G, Anselmo, José Nilson N, Leitao Vasconcelos, Paulo R
• Format: Article
• Language: English
• Subjects: Amino acids; Anesthesia. Intensive care medicine. Transfusions. Cell therapy and gene therapy; Animals; Arginine - pharmacology; Biological and medical sciences; Blood; Body weight; Carcinosarcoma - metabolism; Carcinosarcoma - pathology; Emergency and intensive care: metabolism and nutrition disorders. Enteral and parenteral nutrition; Enteral Nutrition; Intensive care medicine; Ketone Bodies - metabolism; Ketones; Kidney - metabolism; Kidney Neoplasms - metabolism; Kidney Neoplasms - pathology; Kidneys; l-arginine; Liver; Liver - metabolism; Medical sciences; Metabolites; Random Allocation; Rats; Rats, Wistar; Relative humidity; total enteral nutrition; tumor growth; Tumors; Weight Gain - drug effects
• ISSN: 0899-9007; 1873-1244
• DOI: 10.1016/j.nut.2003.12.001

We evaluated the effects of l-arginine–enriched total enteral nutrition (LATEN) on tumor-free and right kidney tumor-bearing rats through the determination of in vivo concentrations of metabolites to better understand intermediary metabolism in this model. Rats were individually housed in wire cages within a controlled environment (25°C and 50% relative humidity) and exposed to a 12-h light-and-dark cycle. Rats comprised the following groups: tumor-free on enteral nutrition plus l-amino acid ( n = 8); tumor-free on enteral nutrition plus l-arginine ( n = 8); tumor bearing on enteral nutrition plus l-amino acids ( n = 8); and tumor bearing on enteral nutrition plus l-arginine ( n = 8). Rats had their right kidneys inoculated with saline or tumor cells and were subjected to laparotomy or gastrostomy on day 1 and received chow diet for the next 2 days. Gastrostomy with enteral nutrition was performed on days 3 to 9. On day 9, body weight gain, tumor growth as volume, in vivo blood (μM/mL), and tissue (μM/g) metabolite concentrations were determined. The Mann-Whitney U test was used to test significance. LATEN in tumor-free rats decreased liver (0.25 ± 0.03 versus 0.13 ± 0.03 μmol/g, P < 0.05) and right kidney (0.13 ± 0.1 versus 0.04 ± 0.00 μmol/g, P < 0.05) ketone body concentrations. LATEN in tumor-bearing rats decreased blood pyruvate (0.17 ± 0.01 versus 0.10 ± 0.008 μM/mL, P < 0.005), lactate (5.2 ± 0.3 versus 2.9 ± 0.28 μM/mL, P < 0.01), and glucose (6.4 ± 0.8 versus 3.7 ± 0.5 μM/mL, P < 0.05). Glucose concentrations decreased in liver (13.9 ± 2.0 versus 4.89 ± 0.6 μM/g, P < 0.005) and tumor (3.5 ± 0.8 versus 1.41 ± 0.3 μM/g, P < 0.05). There were no changes in body weight gain (21 ± 2.0 versus 30.3 ± 3.6 g) or tumor growth (1.53 ± 0.1 versus 1.26 ± 0.01 cm 3). LATEN decreased ketone body concentrations in liver and kidney in tumor-free rats, possibly due to lower ketogenesis and decreased kidney uptake. In tumor-bearing rats, LATEN decreased lacticemia and glycemia and pyruvate blood concentrations. LATEN also reduced liver and tumor glucose concentrations in tumor-bearing animals. The possibility of LATEN-induced insulin and insulin-like growth factor-1 liberation signaling these changes is discussed.