title: Implication of metabolomic profiles to wide thermoneutral zone in Mongolian gerbils (Meriones unguiculatus).
abstract: Mongolian gerbils (Meriones unguiculatus) have evolved a wide thermoneutral zone (26.5-38.9 °C) and high upper critical temperature, and appear to have a high tolerance for heat exposure. Here, we use a metabolomic approach to measure global metabolite profiles for gerbils between lower (27 °C) and upper critical temperatures (38 °C) to investigate the role of metabolomic characterization in maintaining basal metabolic rates within a wide thermoneutral zone. We found that in serum and liver, 14 and 19 metabolites were significantly altered, respectively. In the aerobic respiration-related tricarboxylic cycle (TCA), 5 intermediates (isocitric acid, cis-aconitic acid, α-ketoglutaric acid, fumaric acid and malic acid) were increased in serum in 38 °C animals; however, no such increase was found in the liver. A stable level of hepatic TCA cycle intermediates may be related to the steady state of aerobic respiration at 38 °C. Metabolomic results also revealed that acute heat exposure caused increased oxidative stress and low molecular weight antioxidants in Mongolian gerbils. Increased methionine and 2-hydroxybutyrate suggest an accelerated synthesis of glutathione. Increased urate and its precursors, inosine and hypoxanthine, were detected at 38 °C. Glucuronate, threonate and oxalate involved in ascorbate synthesis and degradation were increased in serum at 38 °C. In conclusion, although dramatic metabolomic variation was found, a stable hepatic TCA cycle may contribute to maintaining a constant basal metabolic rate within a wide thermoneutral zone in Mongolian gerbils.
authors.affiliation: State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China.|University of Chinese Academy of Sciences, Beijing, China.
authors.forename: Yaolong
authors.initials: Y
authors.lastname: Shi
authors.affiliation: State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China.
authors.forename: Dehua
authors.initials: D
authors.lastname: Wang
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000378:metabolism; D001481:Basal Metabolism; D002952:Citric Acid Cycle; D005260:Female; D005849:Gerbillinae / Q000378:metabolism*; D008099:Liver / Q000378:metabolism*; D008297:Male; D055442:Metabolome; D055432:Metabolomics; D018384:Oxidative Stress; D013696:Temperature
chemical_list: D000975:Antioxidants
keywords: basal metabolic rate; gas chromatography-mass spectrometry metabolomics; low molecular weight antioxidants; oxidative stress; thermoneutral zone