title: Hypothalamic agouti-related peptide neurons and the central melanocortin system are crucial mediators of leptin's antidiabetic actions.
abstract: Leptin has beneficial effects on glucose metabolism via actions in the hypothalamus, but the roles of specific subgroups of neurons responsible for these antidiabetic effects remain unresolved. We generated diabetic Lep(ob/ob) or Lepr(db/db) mice lacking or re-expressing leptin receptors (LepRb) in subgroups of neurons to explore their contributions to leptin's glucose-lowering actions. We show that agouti-related peptide (AgRP)-expressing neurons are both required and sufficient to correct hyperglycemia by leptin. LepRb in pro-opiomelanocortin (POMC) neurons or steroidogenic factor-1 (SF1) neurons are not required. Furthermore, normalization of blood glucose by leptin is blunted in Lep(ob/ob)/MC4R-null mice, but not in Lep(ob/ob) mice lacking neuropeptide Y (NPY) or gamma-aminobutyric acid (GABA) in AgRP neurons. Leptin's ability to improve glucose balance is accompanied by a reduction in circulating glucagon. We conclude that AgRP neurons play a crucial role in glucose-lowering actions by leptin and that this requires the melanocortin system, but not NPY and GABA.
authors.affiliation: Department of Medicine, Division of Endocrinology and Metabolism, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA 02215, USA.
authors.forename: Gabriel H M
authors.initials: GH
authors.lastname: Gonçalves
authors.affiliation: Department of Medicine, Division of Endocrinology and Metabolism, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA 02215, USA.
authors.forename: Wenjing
authors.initials: W
authors.lastname: Li
authors.affiliation: Department of Medicine, Division of Endocrinology and Metabolism, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA 02215, USA.
authors.forename: Adriana V C-G
authors.initials: AV
authors.lastname: Garcia
authors.affiliation: Department of Medicine, Division of Endocrinology and Metabolism, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA 02215, USA.
authors.forename: Mariana S
authors.initials: MS
authors.lastname: Figueiredo
authors.affiliation: Department of Medicine, Division of Endocrinology and Metabolism, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA 02215, USA. Electronic address: cbjorbae@bidmc.harvard.edu.
authors.forename: Christian
authors.initials: C
authors.lastname: Bjørbæk
mesh_terms: D054369:Agouti-Related Protein / Q000378:metabolism*; D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D003921:Diabetes Mellitus, Experimental / Q000378:metabolism / Q000517:prevention & control*; D005260:Female; D005934:Glucagon / Q000378:metabolism; D006801:Humans; D007031:Hypothalamus / Q000166:cytology / Q000378:metabolism*; D020738:Leptin / Q000378:metabolism* / Q000494:pharmacology; D008297:Male; D053486:Melanocortins / Q000378:metabolism*; D051379:Mice; D008822:Mice, Transgenic; D009474:Neurons / Q000166:cytology / Q000378:metabolism*; D054411:Receptors, Leptin / Q000378:metabolism*
chemical_list: D054369:Agouti-Related Protein; D001786:Blood Glucose; D020738:Leptin; D053486:Melanocortins; D054411:Receptors, Leptin; D005934:Glucagon