title: Testosterone Rapidly Augments Retrograde Endocannabinoid Signaling in Proopiomelanocortin Neurons to Suppress Glutamatergic Input from Steroidogenic Factor 1 Neurons via Upregulation of Diacylglycerol Lipase-α.
abstract: Testosterone exerts profound effects on reproduction and energy homeostasis. Like other orexigenic hormones, it increases endocannabinoid tone within the hypothalamic feeding circuitry. Therefore, we tested the hypothesis that testosterone upregulates the expression of diacylglycerol lipase (DAGL)α in the hypothalamic arcuate nucleus (ARC) to increase energy intake via enhanced endocannabinoid-mediated retrograde inhibition of anorexigenic proopiomelanocortin (POMC) neurons. Energy intake, meal patterns, and energy expenditure were evaluated in orchidectomized, male guinea pigs treated subcutaneously with testosterone propionate (TP; 400 μg) or its sesame oil vehicle (0.1 mL). TP rapidly increased energy intake, meal size, O2 consumption, CO2 production, and metabolic heat production, all of which were antagonized by prior administration of the DAGL inhibitor orlistat (3 μg) into the third ventricle. These orlistat-sensitive, TP-induced increases in energy intake and expenditure were temporally associated with a significant elevation in ARC DAGLα expression. Electrophysiological recordings in hypothalamic slices revealed that TP potentiated depolarization-induced suppression of excitatory glutamatergic input onto identified ARC POMC neurons, which was also abolished by orlistat (3 μM), the CB1 receptor antagonist AM251 (1 μM), and the AMP-activated protein kinase inhibitor compound C (30 μM) and simulated by transient bath application of the dihydrotestosterone mimetic Cl-4AS-1 (100 nM) and testosterone-conjugated bovine serum albumin (100 nM). Thus, testosterone boosts DAGLα expression to augment retrograde, presynaptic inhibition of glutamate release onto ARC POMC neurons that, in turn, increases energy intake and expenditure. These studies advance our understanding of how androgens work within the hypothalamic feeding circuitry to affect changes in energy balance.
authors.affiliation: Department of Basic Medical Sciences, College of Osteopathic Medicine, Western University of Health Sciences, Pomona, CA, USA.
authors.forename: Kristie
authors.initials: K
authors.lastname: Conde
authors.forename: Carolina
authors.initials: C
authors.lastname: Fabelo
authors.forename: William C
authors.initials: WC
authors.lastname: Krause
authors.forename: Robert
authors.initials: R
authors.lastname: Propst
authors.forename: Jordan
authors.initials: J
authors.lastname: Goethel
authors.forename: Daniel
authors.initials: D
authors.lastname: Fischer
authors.forename: Jin
authors.initials: J
authors.lastname: Hur
authors.forename: Cecilia
authors.initials: C
authors.lastname: Meza
authors.forename: Holly A
authors.initials: HA
authors.lastname: Ingraham
authors.forename: Edward J
authors.initials: EJ
authors.lastname: Wagner
mesh_terms: D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D002540:Cerebral Cortex / Q000166:cytology; D063388:Endocannabinoids / Q000378:metabolism*; D002149:Energy Intake / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004958:Estradiol / Q000031:analogs & derivatives / Q000494:pharmacology; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects; D005260:Female; D018756:GABA Antagonists / Q000494:pharmacology; D018698:Glutamic Acid / Q000378:metabolism*; D006168:Guinea Pigs; D007783:Lactones / Q000494:pharmacology; D008071:Lipoprotein Lipase / Q000235:genetics* / Q000378:metabolism; D008297:Male; D009434:Neural Pathways / Q000187:drug effects / Q000502:physiology; D009474:Neurons / Q000378:metabolism*; D000077403:Orlistat; D011333:Pro-Opiomelanocortin / Q000378:metabolism; D011724:Pyridazines / Q000494:pharmacology; D015398:Signal Transduction / Q000187:drug effects*; D054339:Steroidogenic Factor 1 / Q000378:metabolism; D013739:Testosterone / Q000494:pharmacology*; D015854:Up-Regulation / Q000187:drug effects*
chemical_list: D063388:Endocannabinoids; D004791:Enzyme Inhibitors; D018691:Excitatory Amino Acid Antagonists; D018756:GABA Antagonists; D007783:Lactones; D011724:Pyridazines; D054339:Steroidogenic Factor 1; C074283:estradiol 3-benzoate; D018698:Glutamic Acid; D013739:Testosterone; D004958:Estradiol; D011333:Pro-Opiomelanocortin; D000077403:Orlistat; C049853:gabazine; D008071:Lipoprotein Lipase
keywords: 2-Arachidonoylglycerol; Depolarization-induced suppression of excitation; Diacylglycerol lipase-α; Estradiol; Proopiomelanocortin; Testosterone