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Grant AD, Wilsterman K, Smarr BL, Kriegsfeld LJ. Evidence for a Coupled Oscillator Model of Endocrine Ultradian Rhythms. J Biol Rhythms 2018; 33:475-496. [PMID: 30132387 DOI: 10.1177/0748730418791423] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Whereas long-period temporal structures in endocrine dynamics have been well studied, endocrine rhythms on the scale of hours are relatively unexplored. The study of these ultradian rhythms (URs) has remained nascent, in part, because a theoretical framework unifying ultradian patterns across systems has not been established. The present overview proposes a conceptual coupled oscillator network model of URs in which oscillating hormonal outputs, or nodes, are connected by edges representing the strength of node-node coupling. We propose that variable-strength coupling exists both within and across classic hormonal axes. Because coupled oscillators synchronize, such a model implies that changes across hormonal systems could be inferred by surveying accessible nodes in the network. This implication would at once simplify the study of URs and open new avenues of exploration into conditions affecting coupling. In support of this proposed framework, we review mammalian evidence for (1) URs of the gut-brain axis and the hypothalamo-pituitary-thyroid, -adrenal, and -gonadal axes, (2) UR coupling within and across these axes; and (3) the relation of these URs to body temperature. URs across these systems exhibit behavior broadly consistent with a coupled oscillator network, maintaining both consistent URs and coupling within and across axes. This model may aid the exploration of mammalian physiology at high temporal resolution and improve the understanding of endocrine system dynamics within individuals.
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Affiliation(s)
- Azure D Grant
- The Helen Wills Neuroscience Institute, University of California, Berkeley, California
| | - Kathryn Wilsterman
- Department of Integrative Biology, University of California, Berkeley, California
| | - Benjamin L Smarr
- Department of Psychology, University of California, Berkeley, California
| | - Lance J Kriegsfeld
- The Helen Wills Neuroscience Institute, University of California, Berkeley, California.,Department of Psychology, University of California, Berkeley, California
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Hyötyläinen T, Jerby L, Petäjä EM, Mattila I, Jäntti S, Auvinen P, Gastaldelli A, Yki-Järvinen H, Ruppin E, Orešič M. Genome-scale study reveals reduced metabolic adaptability in patients with non-alcoholic fatty liver disease. Nat Commun 2016; 7:8994. [PMID: 26839171 DOI: 10.1038/ncomms9994] [Citation(s) in RCA: 81] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Accepted: 10/22/2015] [Indexed: 12/14/2022] Open
Abstract
Non-alcoholic fatty liver disease (NAFLD) is a major risk factor leading to chronic liver disease and type 2 diabetes. Here we chart liver metabolic activity and functionality in NAFLD by integrating global transcriptomic data, from human liver biopsies, and metabolic flux data, measured across the human splanchnic vascular bed, within a genome-scale model of human metabolism. We show that an increased amount of liver fat induces mitochondrial metabolism, lipolysis, glyceroneogenesis and a switch from lactate to glycerol as substrate for gluconeogenesis, indicating an intricate balance of exacerbated opposite metabolic processes in glycemic regulation. These changes were associated with reduced metabolic adaptability on a network level in the sense that liver fat accumulation puts increasing demands on the liver to adaptively regulate metabolic responses to maintain basic liver functions. We propose that failure to meet excessive metabolic challenges coupled with reduced metabolic adaptability may lead to a vicious pathogenic cycle leading to the co-morbidities of NAFLD.
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Affiliation(s)
- Tuulia Hyötyläinen
- Department of Systems Medicine, Steno Diabetes Center, Niels Steensens Vej 6, Gentofte, DK-2820, Denmark.,VTT Technical Research Centre of Finland, Espoo, FI-02044 VTT, Finland
| | - Livnat Jerby
- Blavatnik School of Computer Science, Tel Aviv University, Tel Aviv 69978, Israel
| | - Elina M Petäjä
- Department of Medicine, Division of Diabetes, University of Helsinki, Helsinki, FI-00014, Finland.,Minerva Foundation Institute for Medical Research, Helsinki FI-00290, Finland
| | - Ismo Mattila
- Department of Systems Medicine, Steno Diabetes Center, Niels Steensens Vej 6, Gentofte, DK-2820, Denmark.,VTT Technical Research Centre of Finland, Espoo, FI-02044 VTT, Finland
| | - Sirkku Jäntti
- VTT Technical Research Centre of Finland, Espoo, FI-02044 VTT, Finland.,Faculty of Pharmacy, University of Helsinki, Helsinki FI-00014, Finland
| | - Petri Auvinen
- Institute of Biotechnology, DNA Sequencing and Genomics Laboratory, University of Helsinki, Helsinki FI-00014, Finland
| | - Amalia Gastaldelli
- Institute of Clinical Physiology, National Research Council, Pisa 56124, Italy
| | - Hannele Yki-Järvinen
- Department of Medicine, Division of Diabetes, University of Helsinki, Helsinki, FI-00014, Finland.,Minerva Foundation Institute for Medical Research, Helsinki FI-00290, Finland
| | - Eytan Ruppin
- Blavatnik School of Computer Science, Tel Aviv University, Tel Aviv 69978, Israel.,Center for BioInformatics and Computational Biology, Department of Computer Science, University of Maryland, College Park, Maryland 20742, USA
| | - Matej Orešič
- Department of Systems Medicine, Steno Diabetes Center, Niels Steensens Vej 6, Gentofte, DK-2820, Denmark.,VTT Technical Research Centre of Finland, Espoo, FI-02044 VTT, Finland.,Turku Centre for Biotechnology, University of Turku and Åbo Akademi University, Turku FI-20520, Finland
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Osaka T, Kobayashi A, Inoue S. Thermogenesis induced by osmotic stimulation of the intestines in the rat. J Physiol 2001; 532:261-9. [PMID: 11283240 PMCID: PMC2278526 DOI: 10.1111/j.1469-7793.2001.0261g.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Infusion of 5-20% glucose, 1.8-3.6% NaCl, 20% methylglucose, 20% fructose, or 5-10% solutions of various amino acids (10 ml x kg(-1)) into the duodenum induced dose-dependent thermogenesis in urethane-anaesthetized rats. In contrast, infusion of 0.9% NaCl, distilled water, or safflower oil had no effect on the metabolic rate. Infusion of 7.2% urea induced a small and transient increase in the metabolic rate. These results suggested that the thermogenesis was caused mainly by changes in osmolality rather than by a specific action of the different solute molecules. The respiratory exchange ratio increased after the infusion of glucose, fructose, glycine, or serine, did not change after the infusion of NaCl, methylglucose, safflower oil, or distilled water, and decreased after infusion of arginine. Therefore, there was no relationship between substrate utilization and the occurrence of thermogenesis. Intestinal infusion of 3.6% NaCl elevated the plasma osmolality, with a plateau increase of approximately 20 mosmol x kg(-1). However, intravenous infusion of the same amount of NaCl induced a significantly smaller thermogenic response, although it elevated the plasma osmolality with a time course and magnitude similar to those obtained after the intestinal infusion. Infusion of NaCl into the hepatic portal vein or the peritoneal cavity also produced a significantly small thermogenic response. These results suggested an intestinal or mesenteric location for osmoreceptors. To test for possible stimulation of intestinal osmoreceptors after intake of a normal meal, we measured the osmolality of the intestinal contents. The osmolality of the duodeno-jejunal contents was 600-800 mosmol kg-1, whereas the plasma osmolality was 306 +/- 1 mosmol x kg(-1), which suggests that the intestinal osmoreceptors are stimulated after meals and are involved in diet-induced thermogenesis.
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Affiliation(s)
- T Osaka
- National Institute of Health and Nutrition, Shinjuku 162-8636, Japan.
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