- 作者：Niels Kristian Aagaard ; Thorbjø ; rn Grø ; fte ; Jacob Greisen ; Kjell Malmlö ; f ; Peter B Johansen ; Henning Grø ; nbæ ; k ; Hans Ø ; rskov ; Niels Tygstrup ; Hendrik Vilstrup
- 关键词：Growth hormone ; Growth hormone secretagogue ; Glucocorticoids ; Protein metabolism ; Amino acids ; Gene expression
- 刊名：Growth Hormone IGF Research
- 出版年：2009
- 出版时间：October 2009
- 年：2009
- 卷：19
- 期：5
- 页码：426-431
- 全文大小：302 K
ObjectivesGrowth 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 α-amino-nitrogen conversion during steroid-induced catabolism.Design
Five groups of rats were included: (1) free-fed controls (2) pair-fed controls (3) prednisolone (delcortol, 4 mg × kg−1 × day−1) (4) prednisolone and GH (1 mg × kg−1 × day−1) (5) prednisolone and Ipamorelin (0.5 mg × kg−1 × 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.
Conclusion
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.