title: Growth hormone and growth hormone secretagogue effects on nitrogen balance and urea synthesis in steroid treated rats.
abstract: OBJECTIVE
  Growth hormone (GH) reduces the catabolic side effects of steroid treatment via effects on the amino-nitrogen metabolism. Ipamorelin is a synthetic peptide with GH releasing properties. We wished to study the metabolic effects of Ipamorelin and GH on selected hepatic measures of alpha-amino-nitrogen conversion during steroid-induced catabolism.
  
  
  METHODS
  Five groups of rats were included: (1) free-fed controls (2) pair-fed controls (3) prednisolone (delcortol, 4 mg x kg(-1) x day(-1)) (4) prednisolone and GH (1 mg x kg(-1) x day(-1)) (5) prednisolone and Ipamorelin (0.5 mg x kg(-1) x day(-1)). After seven days the hepatic capacity of urea-N synthesis (CUNS) was determined in parallel with measurements of liver mRNA levels of urea cycle enzymes, whole-body N-balance, and N-contents of various organs.
  
  
  RESULTS
  Compared to pair-fed controls, prednisolone increased CUNS (p<0.01) as well as the expression of urea cycle genes (p<0.01), and decreased N-balance (p<0.01) as well as organ N-contents (p<0.05). Compared to prednisolone treated animals, co-administration of GH reduced CUNS by 33% (p<0.01), normalized urea cycle gene expression, improved N-balance 2.5-fold, and normalized or improved organ N-contents. In prednisolone treated rats Ipamorelin reduced CUNS by 20% (p<0.05), decreased the expression of urea cycle enzymes, neutralised N-balance, and normalized or improved organ N-contents.
  
  
  CONCLUSIONS
  Accelerated nitrogen wasting in the liver and other organs caused by prednisolone treatment was counteracted by treatment with either GH or its secretagogue Ipamorelin, though at the doses given less efficiently by the latter. This functional study of animals confirms that the GH secretagogue exerts GH related metabolic effects and may be useful in the treatment of steroid-induced catabolism.
authors.affiliation: Department of Medicine V (Hepatology and Gastroenterology), Aarhus University Hospital, DK-8000 Aarhus C, Denmark. nielaaga@rm.dk
authors.forename: Niels Kristian
authors.initials: NK
authors.lastname: Aagaard
authors.forename: Thorbjørn
authors.initials: T
authors.lastname: Grøfte
authors.forename: Jacob
authors.initials: J
authors.lastname: Greisen
authors.forename: Kjell
authors.initials: K
authors.lastname: Malmlöf
authors.forename: Peter B
authors.initials: PB
authors.lastname: Johansen
authors.forename: Henning
authors.initials: H
authors.lastname: Grønbaek
authors.forename: Hans
authors.initials: H
authors.lastname: Ørskov
authors.forename: Niels
authors.initials: N
authors.lastname: Tygstrup
authors.forename: Hendrik
authors.initials: H
authors.lastname: Vilstrup
mesh_terms: D000818:Animals; D013006:Growth Hormone / Q000378:metabolism / Q000494:pharmacology*; D007334:Insulin-Like Growth Factor I / Q000378:metabolism; D008099:Liver / Q000378:metabolism; D009584:Nitrogen / Q000378:metabolism*; D009929:Organ Size; D011239:Prednisolone / Q000494:pharmacology; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D014508:Urea / Q000378:metabolism*
chemical_list: D012333:RNA, Messenger; D007334:Insulin-Like Growth Factor I; D014508:Urea; D013006:Growth Hormone; D011239:Prednisolone; D009584:Nitrogen