title: Human adipose tissue expresses intrinsic circadian rhythm in insulin sensitivity.
abstract: In humans, insulin sensitivity varies according to time of day, with decreased values in the evening and at night. Mechanisms responsible for the diurnal variation in insulin sensitivity are unclear. We investigated whether human adipose tissue (AT) expresses intrinsic circadian rhythms in insulin sensitivity that could contribute to this phenomenon. Subcutaneous and visceral AT biopsies were obtained from extremely obese participants (body mass index, 41.8 ± 6.3 kg/m(2); 46 ± 11 y) during gastric-bypass surgery. To assess the rhythm in insulin signaling, AKT phosphorylation was determined every 4 h over 24 h in vitro in response to different insulin concentrations (0, 1, 10, and 100 nM). Data revealed that subcutaneous AT exhibited robust circadian rhythms in insulin signaling (P < 0.00001). Insulin sensitivity reached its maximum (acrophase) around noon, being 54% higher than during midnight (P = 0.009). The amplitude of the rhythm was positively correlated with in vivo sleep duration (r = 0.53; P = 0.023) and negatively correlated with in vivo bedtime (r = -0.54; P = 0.020). No circadian rhythms were detected in visceral AT (P = 0.643). Here, we demonstrate the relevance of the time of the day for how sensitive AT is to the effects of insulin. Subcutaneous AT shows an endogenous circadian rhythm in insulin sensitivity that could provide an underlying mechanism for the daily rhythm in systemic insulin sensitivity.-Carrasco-Benso, M. P., Rivero-Gutierrez, B., Lopez-Minguez, J., Anzola, A., Diez-Noguera, A., Madrid, J. A., Lujan, J. A., Martínez-Augustin, O., Scheer, F. A. J. L., Garaulet, M. Human adipose tissue expresses intrinsic circadian rhythm in insulin sensitivity.
authors.affiliation: Department of Physiology, Faculty of Biology, Biomedical Research Institute of Murcia (IMIB)-Arrixaca, University of Murcia, Murcia, Spain;
authors.forename: Maria P
authors.initials: MP
authors.lastname: Carrasco-Benso
authors.affiliation: Department of Biochemistry and Molecular Biology II, Biomedical Research Networking Center in Hepatic and Digestive Diseases (CIBEREHD), School of Pharmacy, Instituto de Investigación Biosanitaria de Granada, University of Granada, Granada, Spain;
authors.forename: Belen
authors.initials: B
authors.lastname: Rivero-Gutierrez
authors.affiliation: Department of Physiology, Faculty of Biology, Biomedical Research Institute of Murcia (IMIB)-Arrixaca, University of Murcia, Murcia, Spain;
authors.forename: Jesus
authors.initials: J
authors.lastname: Lopez-Minguez
authors.affiliation: Department of Biochemistry and Molecular Biology II, Biomedical Research Networking Center in Hepatic and Digestive Diseases (CIBEREHD), School of Pharmacy, Instituto de Investigación Biosanitaria de Granada, University of Granada, Granada, Spain;
authors.forename: Andrea
authors.initials: A
authors.lastname: Anzola
authors.affiliation: Department of Physiology, Faculty of Pharmacy, University of Barcelona, Barcelona, Spain;
authors.forename: Antoni
authors.initials: A
authors.lastname: Diez-Noguera
authors.affiliation: Department of Physiology, Faculty of Biology, Biomedical Research Institute of Murcia (IMIB)-Arrixaca, University of Murcia, Murcia, Spain;
authors.forename: Juan A
authors.initials: JA
authors.lastname: Madrid
authors.affiliation: General Surgery Service, University Hospital Virgen de la Arrixaca, Murcia, Spain;
authors.forename: Juan A
authors.initials: JA
authors.lastname: Lujan
authors.affiliation: Department of Biochemistry and Molecular Biology II, Biomedical Research Networking Center in Hepatic and Digestive Diseases (CIBEREHD), School of Pharmacy, Instituto de Investigación Biosanitaria de Granada, University of Granada, Granada, Spain;
authors.forename: Olga
authors.initials: O
authors.lastname: Martínez-Augustin
authors.affiliation: Division of Sleep and Circadian Disorders, Brigham and Women's Hospital, Boston, Massachusetts, USA; and Division of Sleep Medicine, Harvard Medical School, Boston, Massachusetts, USA fscheer@bwh.harvard.edu.
authors.forename: Frank A J L
authors.initials: FA
authors.lastname: Scheer
authors.affiliation: Department of Physiology, Faculty of Biology, Biomedical Research Institute of Murcia (IMIB)-Arrixaca, University of Murcia, Murcia, Spain; garaulet@um.es.
authors.forename: Marta
authors.initials: M
authors.lastname: Garaulet
mesh_terms: D000273:Adipose Tissue / Q000502:physiology*; D000328:Adult; D002940:Circadian Rhythm / Q000502:physiology*; D004334:Drug Administration Schedule; D006801:Humans; D007328:Insulin / Q000494:pharmacology*; D007333:Insulin Resistance; D008875:Middle Aged; D009765:Obesity; D010766:Phosphorylation; D051057:Proto-Oncogene Proteins c-akt / Q000235:genetics / Q000378:metabolism; D012890:Sleep
chemical_list: D007328:Insulin; D051057:Proto-Oncogene Proteins c-akt
keywords: diabetes; glucose tolerance; obesity