Adrenal expression of orexin receptor subtypes is differentially regulated in experimental streptozotocin induced type-1 diabetes.
Orexins (hypocretins) are involved in the regulation of energy homeostasis and sleeping behavior. Orexins were also implicated in the regulation of neuroendocrine and autonomic functions. Recent data show the expression of orexin receptors within the hypothalamic-pituitary-adrenal (HPA) axis and suggest specific actions of orexins at the pituitary and adrenal glands. To further evaluate the role of orexin in the HPA axis, we investigated the mRNA expression of prepro-orexin (PPO) and orexin receptors within the HPA axis of streptozotocin-injected (STZ) rats showing type-1 like diabetes. PPO, as well as OX(1) and OX(2) receptor levels were analyzed by quantitative real-time PCR (qPCR). STZ rats were characterized by decreased body weight, plasma insulin, and leptin levels and by increased plasma glucose. Hypothalamic PPO mRNA levels were significantly reduced in STZ compared to non-diabetic control rats. No differences were found in the mRNA levels of hypothalamic or pituitary OX(1) and OX(2) receptors between control and STZ rats. In adrenals, OX(1) receptor mRNA levels were significantly elevated in STZ rats while OX(2) receptors were significantly reduced. Our results imply distinct functions of adrenal orexin receptor subtypes during type-1 like diabetes.
Jöhren
Olaf
O
Institute of Experimental and Clinical Pharmacology and Toxicology, University of Lübeck, Ratzeburger Allee 160, D-23538 Lübeck, Germany. Joehren@uni-luebeck.de
Gremmels
Julia A F
JA
Qadri
Fatimunnisa
F
Dendorfer
Andreas
A
Dominiak
Peter
P
D000311:Adrenal Glands / Q000378:metabolism*; D000818:Animals; D001786:Blood Glucose / Q000032:analysis; D001835:Body Weight; D003922:Diabetes Mellitus, Type 1 / Q000139:chemically induced / Q000378:metabolism*; D007031:Hypothalamus / Q000502:physiology; D007328:Insulin / Q000097:blood; D047908:Intracellular Signaling Peptides and Proteins / Q000097:blood / Q000378:metabolism; D020738:Leptin / Q000097:blood; D008297:Male; D009479:Neuropeptides / Q000097:blood / Q000378:metabolism; D064446:Orexin Receptors; D000068797:Orexins; D010902:Pituitary Gland / Q000502:physiology; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D017207:Rats, Sprague-Dawley; D043562:Receptors, G-Protein-Coupled / Q000235:genetics / Q000378:metabolism*; D018013:Receptors, Neuropeptide / Q000235:genetics / Q000378:metabolism*; D013311:Streptozocin / Q000494:pharmacology
D001786:Blood Glucose; D007328:Insulin; D047908:Intracellular Signaling Peptides and Proteins; D020738:Leptin; D009479:Neuropeptides; D064446:Orexin Receptors; D000068797:Orexins; D012333:RNA, Messenger; D043562:Receptors, G-Protein-Coupled; D018013:Receptors, Neuropeptide; D013311:Streptozocin