L-Citrulline acts as potential hypothermic agent to afford thermotolerance in chicks. (October 2017)

• Record Type: Journal Article
• Authors: Chowdhury, Vishwajit S.; Han, Guofeng; Bahry, Mohammad A.; Tran, Phuong V.; Do, Phong H.; Yang, Hui; Furuse, Mitsuhiro
• Is Part Of: Journal of thermal biology. Volume 69(2017)
• Page Start: 163
• Page End: 170
• Publication Date: 2017-10
• Subjects: L-Citrulline -- Hypothermia -- Thermotolerance -- Nitric oxide -- Plasma glucose -- Chicks; Thermobiology -- Periodicals; Temperature -- Periodicals; Biology -- Periodicals; Thermobiologie -- Périodiques; Thermobiology; Periodicals; 571.46
• DOI: 10.1016/j.jtherbio.2017.07.007
• Languages: English
• ISSNs: 0306-4565

Abstract

Abstract: Recently we demonstrated that L-citrulline (L-Cit) causes hypothermia in chicks. However, the question of how L-Cit mediates hypothermia remained elusive. Thus, the objective of this study was to examine some possible factors in the process of L-Cit-mediated hypothermia and to confirm whether L-Cit can also afford thermotolerance in young chicks. Chicks were subjected to oral administration of L-Cit along with intraperitoneal injection of a nitric oxide synthase (NOS) inhibitor, N G -nitro-l -arginine methyl ester HCl (L-NAME), to examine the involvement of NO in the process of hypothermia. Food intake and plasma metabolites were also analyzed after oral administration of L-Cit in chicks. To examine thermotolerance, chicks were orally administered with a single dose of L-Cit (15 mmol/10 ml/kg body weight) or the same dose twice within a short interval of 1 h (dual oral administration) before the exposure to high ambient temperature (35 ± 1 °C) for 180 min. Although the rectal temperature was reduced following administration of L-Cit, L-NAME caused a greater reduction. L-NAME reduced total NO2 and NO3 (NOx) in plasma, which confirmed its inhibitory effect on NO. A single oral administration of L-Cit mediated a persistent state of hypothermia for the 300 min of the study without affecting food intake. It was further found that plasma glucose was significantly lower in L-Cit-treated chicks. Dual oral administration of L-Cit, but not a single oral administration, afforded thermotolerance without a significant change in plasma NOx in chicks. In conclusion, our results suggest that L-Cit-mediated hypothermia and thermotolerance may not be involved in NO production. L-Cit-mediated thermotolerance further suggests that L-Cit may serve as an important nutritional supplement that could help in coping with summer heat. Highlights: L-Citrulline caused hypothermia without significant changes in nitric oxide levels. Hypoglycemia occurred in L-citrulline-mediated hypothermic chicks. L-Citrulline-mediated hypothermia afforded thermotolerance.