title: Intracerebroventricular O-n-octanoylated ghrelin and its splice variant-induced feeding is blocked by insulin, independent of obestatin or CRF receptor, in satiated rats.
abstract: OBJECTIVE
  The purpose of this study was to investigate the impact of intracerebroventricular (ICV) injection of the two endogenous forms of acyl ghrelin, O-n-octanoylated ghrelin and des-Gln¹⁴-ghrelin, on feeding behavior, as well as their interactions with insulin, obestatin, and corticotropin-releasing factor receptor (CRF-R) antagonist in the forebrain to influence food intake.
  
  
  METHODS
  We examined the food intake in conscious, freely fed rats, which were chronically implanted with ICV catheters.
  
  
  RESULTS
  O-n-octanoylated ghrelin and des-Gln¹⁴-ghrelin (0.1 nmol/rat) were equally potent in stimulating food intake in freely fed rats, up to 8 h after ICV injection (P < 0.05). In contrast, ICV administration of insulin (8 mU/rat), obestatin (2 nmol/rat), and astressin (2 nmol/rat), a specific CRF-R antagonist, did not modify feeding in freely fed rats. Furthermore, pretreatment with ICV insulin (P < 0.01), but not obestatin or astressin, at the abovementioned dose, blocked central acyl-ghrelin-induced hyperphagic effects.
  
  
  CONCLUSIONS
  ICV O-n-octanoylated ghrelin and its splice variant, des-Gln¹⁴-ghrelin, are equally potent to elicit food intake in freely fed rats, while these feeding-stimulating effects are opposed by insulin, but independent of obestatin and endogenous CRF-R in the forebrain.
authors.affiliation: Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan. chency@vghtpe.gov.tw
authors.forename: Chih-Yen
authors.initials: CY
authors.lastname: Chen
authors.forename: Chang-Youh
authors.initials: CY
authors.lastname: Tsai
authors.forename: Wei-Jei
authors.initials: WJ
authors.lastname: Lee
authors.forename: Wen-Jinn
authors.initials: WJ
authors.lastname: Liaw
authors.forename: Chi-Huei
authors.initials: CH
authors.lastname: Chiang
authors.forename: Shung-Tai
authors.initials: ST
authors.lastname: Ho
authors.forename: Shou-Dong
authors.initials: SD
authors.lastname: Lee
mesh_terms: D000818:Animals; D019167:Appetite Stimulants / Q000008:administration & dosage / Q000037:antagonists & inhibitors / Q000378:metabolism; D001522:Behavior, Animal / Q000187:drug effects; D002408:Catheters, Indwelling; D005247:Feeding Behavior / Q000187:drug effects; D054439:Ghrelin / Q000008:administration & dosage / Q000037:antagonists & inhibitors* / Q000378:metabolism; D006727:Hormone Antagonists / Q000008:administration & dosage / Q000494:pharmacology; D006963:Hyperphagia / Q000378:metabolism*; D007276:Injections, Intraventricular; D007328:Insulin / Q000008:administration & dosage / Q000378:metabolism*; D008297:Male; D009419:Nerve Tissue Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism; D009474:Neurons / Q000187:drug effects / Q000378:metabolism; D036361:Peptide Hormones / Q000008:administration & dosage / Q000378:metabolism*; D016548:Prosencephalon / Q000187:drug effects / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D018019:Receptors, Corticotropin-Releasing Hormone / Q000037:antagonists & inhibitors / Q000378:metabolism*; D013997:Time Factors
chemical_list: D019167:Appetite Stimulants; D054439:Ghrelin; D006727:Hormone Antagonists; D007328:Insulin; D009419:Nerve Tissue Proteins; D036361:Peptide Hormones; D018019:Receptors, Corticotropin-Releasing Hormone; C412225:ghrelin, des-Gln(14)-; C505798:obestatin, rat