Ami Nakajima, Ryo Yamaguchi, Maya Sasazaki, Akinori Ishihara, Kiyoshi Yamauchi
{"title":"Adult male Xenopus laevis can tolerate months of fasting by catabolizing carbohydrates and lipids.","authors":"Ami Nakajima, Ryo Yamaguchi, Maya Sasazaki, Akinori Ishihara, Kiyoshi Yamauchi","doi":"10.1007/s00360-023-01478-5","DOIUrl":null,"url":null,"abstract":"<p><p>The African clawed frog, Xenopus laevis, has been reported to tolerate long-term fasting without dormancy. However, the strategies for energy acquisition during fasting are unclear in this species. We performed 3- and 7-month fasting experiments to investigate how the metabolism of male X. laevis changes during long-term fasting. We found that the levels of several serum biochemical parameters, such as glucose, triglycerides, and free fatty acids, as well as liver glycogen were reduced after 3 months of fasting, whereas after 7 months of fasting, triglyceride levels were reduced, and fat body wet weight was lower than that of fed group indicating the onset of lipid catabolism. In addition, transcript levels of gluconeogenic genes, such as pck1, pck2, g6pc1.1, and g6pc1.2, were increased in the livers of animals fasted for 3 months, suggesting upregulation of gluconeogenesis. Our results raise the possibility that male X. laevis can tolerate much longer fasting than previously reported by utilizing several energy storage molecules. Further investigation of the effects of prolonged fasting on the metabolic switches from carbohydrates to lipids or amino acids in X. laevis is required.</p>","PeriodicalId":56033,"journal":{"name":"Journal of Comparative Physiology B-Biochemical Systems and Environmental Physiology","volume":null,"pages":null},"PeriodicalIF":1.7000,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Comparative Physiology B-Biochemical Systems and Environmental Physiology","FirstCategoryId":"99","ListUrlMain":"https://doi.org/10.1007/s00360-023-01478-5","RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q4","JCRName":"PHYSIOLOGY","Score":null,"Total":0}
引用次数: 0
Abstract
The African clawed frog, Xenopus laevis, has been reported to tolerate long-term fasting without dormancy. However, the strategies for energy acquisition during fasting are unclear in this species. We performed 3- and 7-month fasting experiments to investigate how the metabolism of male X. laevis changes during long-term fasting. We found that the levels of several serum biochemical parameters, such as glucose, triglycerides, and free fatty acids, as well as liver glycogen were reduced after 3 months of fasting, whereas after 7 months of fasting, triglyceride levels were reduced, and fat body wet weight was lower than that of fed group indicating the onset of lipid catabolism. In addition, transcript levels of gluconeogenic genes, such as pck1, pck2, g6pc1.1, and g6pc1.2, were increased in the livers of animals fasted for 3 months, suggesting upregulation of gluconeogenesis. Our results raise the possibility that male X. laevis can tolerate much longer fasting than previously reported by utilizing several energy storage molecules. Further investigation of the effects of prolonged fasting on the metabolic switches from carbohydrates to lipids or amino acids in X. laevis is required.
期刊介绍:
The Journal of Comparative Physiology B publishes peer-reviewed original articles and reviews on the comparative physiology of invertebrate and vertebrate animals. Special emphasis is placed on integrative studies that elucidate mechanisms at the whole-animal, organ, tissue, cellular and/or molecular levels. Review papers report on the current state of knowledge in an area of comparative physiology, and directions in which future research is needed.