1
|
Lam T, McLean M, Hayden A, Poljak A, Cheema B, Gurney H, Stone G, Bahl N, Reddy N, Shahidipour H, Birzniece V. A potent liver-mediated mechanism for loss of muscle mass during androgen deprivation therapy. Endocr Connect 2019; 8:605-615. [PMID: 30991356 PMCID: PMC6510709 DOI: 10.1530/ec-19-0179] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Accepted: 04/15/2019] [Indexed: 12/25/2022]
Abstract
CONTEXT Androgen deprivation therapy (ADT) in prostate cancer results in muscular atrophy, due to loss of the anabolic actions of testosterone. Recently, we discovered that testosterone acts on the hepatic urea cycle to reduce amino acid nitrogen elimination. We now hypothesize that ADT enhances protein oxidative losses by increasing hepatic urea production, resulting in muscle catabolism. We also investigated whether progressive resistance training (PRT) can offset ADT-induced changes in protein metabolism. OBJECTIVE To investigate the effect of ADT on whole-body protein metabolism and hepatic urea production with and without a home-based PRT program. DESIGN A randomized controlled trial. PATIENTS AND INTERVENTION Twenty-four prostate cancer patients were studied before and after 6 weeks of ADT. Patients were randomized into either usual care (UC) (n = 11) or PRT (n = 13) starting immediately after ADT. MAIN OUTCOME MEASURES The rate of hepatic urea production was measured by the urea turnover technique using 15N2-urea. Whole-body leucine turnover was measured, and leucine rate of appearance (LRa), an index of protein breakdown and leucine oxidation (Lox), a measure of irreversible protein loss, was calculated. RESULTS ADT resulted in a significant mean increase in hepatic urea production (from 427.6 ± 18.8 to 486.5 ± 21.3; P < 0.01) regardless of the exercise intervention. Net protein loss, as measured by Lox/Lra, increased by 12.6 ± 4.9% (P < 0.05). PRT preserved lean body mass without affecting hepatic urea production. CONCLUSION As early as 6 weeks after initiation of ADT, the suppression of testosterone increases protein loss through elevated hepatic urea production. Short-term PRT was unable to offset changes in protein metabolism during a state of profound testosterone deficiency.
Collapse
Affiliation(s)
- Teresa Lam
- School of Medicine, Western Sydney University, Penrith, New South Wales, Australia
- Department of Diabetes and Endocrinology, Blacktown Hospital, Blacktown, New South Wales, Australia
- Department of Diabetes and Endocrinology, Westmead Hospital, Westmead, New South Wales, Australia
- Correspondence should be addressed to T Lam:
| | - Mark McLean
- School of Medicine, Western Sydney University, Penrith, New South Wales, Australia
- Department of Diabetes and Endocrinology, Blacktown Hospital, Blacktown, New South Wales, Australia
| | - Amy Hayden
- Department of Radiation Oncology, Blacktown Hospital, Blacktown, New South Wales, Australia
- Crown Princess Mary Cancer Centre, Westmead Hospital, Westmead, New South Wales, Australia
| | - Anne Poljak
- Bioanalytical Mass Spectrometry Facility and School of Medical Sciences, UNSW Sydney, Sydney, New South Wales, Australia
| | - Birinder Cheema
- School of Science and Health, Western Sydney University, Penrith, New South Wales, Australia
| | - Howard Gurney
- Crown Princess Mary Cancer Centre, Westmead Hospital, Westmead, New South Wales, Australia
| | - Glenn Stone
- School of Computing, Engineering and Mathematics, Western Sydney University, Penrith, New South Wales, Australia
| | - Neha Bahl
- School of Medicine, Western Sydney University, Penrith, New South Wales, Australia
| | - Navneeta Reddy
- Department of Diabetes and Endocrinology, Blacktown Hospital, Blacktown, New South Wales, Australia
- Garvan Institute of Medical Research, Darlinghurst, New South Wales, Australia
| | - Haleh Shahidipour
- School of Medicine, Western Sydney University, Penrith, New South Wales, Australia
- Department of Diabetes and Endocrinology, Blacktown Hospital, Blacktown, New South Wales, Australia
- School of Medicine, UNSW Sydney, Sydney, New South Wales, Australia
- Translational Health Research Institute, Penrith, New South Wales, Australia
| | - Vita Birzniece
- School of Medicine, Western Sydney University, Penrith, New South Wales, Australia
- Department of Diabetes and Endocrinology, Blacktown Hospital, Blacktown, New South Wales, Australia
- Garvan Institute of Medical Research, Darlinghurst, New South Wales, Australia
- School of Medicine, UNSW Sydney, Sydney, New South Wales, Australia
- Translational Health Research Institute, Penrith, New South Wales, Australia
| |
Collapse
|
2
|
Abstract
PURPOSE OF REVIEW The purpose of this review is to summarize recent findings on hepatic actions of androgens in the regulation of protein, lipid and glucose metabolism. The rationale for liver-targeted testosterone use will be provided. RECENT FINDINGS Liver-targeted testosterone administration, via the oral route, induces protein anabolic effect by reducing the rate of protein oxidation to a similar extent to that of systemic testosterone administration. Recent evidence indicates that testosterone exerts whole-body anabolic effect through inhibition of nitrogen loss via the hepatic urea cycle. Several hepatic effects of androgens, particularly on glucose metabolism, are direct and take place before any changes in body composition occur. This includes an increase in insulin secretion and sensitivity, and reduction in hepatic glucose output by testosterone. Furthermore, lack of testosterone in the liver exacerbates diet-induced impairment in glucose metabolism. In the liver, androgens induce the full spectrum of metabolic changes through interaction with growth hormone or aromatization to estradiol. SUMMARY Liver-targeted testosterone therapy may open up a new approach to achieve whole-body anabolism without systemic side-effects. Aromatizable androgens may be superior to nonaromatizable androgens in inducing a complex spectrum of direct, estrogen-mediated and other hormone-mediated effects of androgens.
Collapse
Affiliation(s)
- Vita Birzniece
- School of Medicine, Western Sydney University, Sydney
- Department of Diabetes and Endocrinology, Blacktown Hospital, Blacktown
- Garvan Institute of Medical Research, Sydney
- School of Medicine, University of New South Wales, Sydney, New South Wales, Australia
| |
Collapse
|
3
|
Lam T, Poljak A, McLean M, Bahl N, Ho KKY, Birzniece V. Testosterone prevents protein loss via the hepatic urea cycle in human. Eur J Endocrinol 2017; 176:489-496. [PMID: 28122810 DOI: 10.1530/eje-16-0868] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Revised: 01/05/2017] [Accepted: 01/25/2017] [Indexed: 11/08/2022]
Abstract
CONTEXT The urea cycle is a rate-limiting step for amino acid nitrogen elimination. The rate of urea synthesis is a true indicator of whole-body protein catabolism. Testosterone reduces protein and nitrogen loss. The effect of testosterone on hepatic urea synthesis in humans has not been studied. OBJECTIVE To determine whether testosterone reduces hepatic urea production. DESIGN An open-label study. PATIENTS AND INTERVENTION Eight hypogonadal men were studied at baseline, and after two weeks of transdermal testosterone replacement (Testogel, 100 mg/day). MAIN OUTCOMES MEASURES The rate of hepatic urea synthesis was measured by the urea turnover technique using stable isotope methodology, with 15N2-urea as tracer. Whole-body leucine turnover was measured, from which leucine rate of appearance (LRa), an index of protein breakdown and leucine oxidation (Lox), a measure of irreversible protein loss, were calculated. RESULTS Testosterone administration significantly reduced the rate of hepatic urea production (from 544.4 ± 71.8 to 431.7 ± 68.3 µmol/min; P < 0.01), which was paralleled by a significant reduction in serum urea concentration. Testosterone treatment significantly reduced net protein loss, as measured by percent Lox/LRa, by 19.3 ± 5.8% (P < 0.05). There was a positive association between Lox and hepatic urea production at baseline (r2 = 0.60, P < 0.05) and after testosterone administration (r2 = 0.59, P < 0.05). CONCLUSION Testosterone replacement reduces protein loss and hepatic urea synthesis. We conclude that testosterone regulates whole-body protein metabolism by suppressing the urea cycle.
Collapse
Affiliation(s)
- Teresa Lam
- School of MedicineWestern Sydney University, Penrith, New South Wales, Australia
- Department of Diabetes and EndocrinologyBlacktown Hospital, Blacktown, New South Wales, Australia
| | - Anne Poljak
- Bioanalytical Mass Spectrometry Facility and School of Medical SciencesUniversity of New South Wales, New South Wales, Australia
| | - Mark McLean
- School of MedicineWestern Sydney University, Penrith, New South Wales, Australia
- Department of Diabetes and EndocrinologyBlacktown Hospital, Blacktown, New South Wales, Australia
| | - Neha Bahl
- School of MedicineWestern Sydney University, Penrith, New South Wales, Australia
- Garvan Institute of Medical ResearchSydney, New South Wales, Australia
| | - Ken K Y Ho
- Garvan Institute of Medical ResearchSydney, New South Wales, Australia
- Centres of Health ResearchPrincess Alexandra Hospital, Brisbane, Queensland, Australia
| | - Vita Birzniece
- School of MedicineWestern Sydney University, Penrith, New South Wales, Australia
- Department of Diabetes and EndocrinologyBlacktown Hospital, Blacktown, New South Wales, Australia
- Garvan Institute of Medical ResearchSydney, New South Wales, Australia
- School of MedicineUniversity of New South Wales, New South Wales, Australia
| |
Collapse
|
4
|
Aagaard NK, Grøfte T, Greisen J, Malmlöf K, Johansen PB, Grønbaek H, Ørskov H, Tygstrup N, Vilstrup H. Growth hormone and growth hormone secretagogue effects on nitrogen balance and urea synthesis in steroid treated rats. Growth Horm IGF Res 2009; 19:426-431. [PMID: 19231263 DOI: 10.1016/j.ghir.2009.01.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/25/2007] [Revised: 01/06/2009] [Accepted: 01/11/2009] [Indexed: 11/23/2022]
Abstract
OBJECTIVES 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. DESIGN 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. 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.
Collapse
Affiliation(s)
- Niels Kristian Aagaard
- Department of Medicine V (Hepatology and Gastroenterology), Aarhus University Hospital, DK-8000 Aarhus C, Denmark.
| | | | | | | | | | | | | | | | | |
Collapse
|
5
|
Velez JC, Donkin SS. Bovine Somatotropin Increases Hepatic Phosphoenolpyruvate Carboxykinase mRNA in Lactating Dairy Cows,. J Dairy Sci 2004; 87:1325-35. [PMID: 15290980 DOI: 10.3168/jds.s0022-0302(04)73282-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Somatotropin (ST) increases milk production and through coordinated changes in hepatic glucose synthesis and amino acid metabolism in dairy cows. The objective of this study was to determine the effects of ST on hepatic mRNA expression for phosphoenolpyruvate carboxykinase (PEPCK) and pyruvate carboxylase (PC), enzymes that are critical to the synthesis of glucose in liver and hepatic mRNA expression for carbamylphosphate synthetase I (CPS-I), argininosuccinate synthetase (AS), and ornithine transcarbamylase (OTC), critical enzymes of the urea cycle. Eighteen cows were randomly allocated to 2 treatment groups and received either recombinant bovine ST (Posilac; Monsanto, St. Louis, MO) or saline injections at 14-d intervals during a 42-d period. Expression of mRNA was determined using Northern blot analysis. Nuclei, isolated from liver biopsy samples, were used to determine effects of ST on transcription rate of PEPCK. Milk production was increased with ST (37.3 vs. 35.1+/-0.6 kg/ d). Plasma NEFA was increased with ST (299 vs. 156+/-34 microM). There were no differences in the expression of CPS-I, AS, and OTC mRNA with ST. Expression of PEPCK and IGF-I mRNA were increased with ST but PC mRNA was unchanged. The data indicate increased PEPCK mRNA in cows given ST and indicates a greater capacity for gluconeogenesis from gluconeogenic precursors that form oxaloacetate. The effects of ST to elevate PEPCK mRNA expression require chronic administration and involve increased transcription of the PEPCK gene.
Collapse
Affiliation(s)
- J C Velez
- Department of Animal Sciences, Purdue University, West Lafayette, IN 47907, USA
| | | |
Collapse
|
6
|
Woodruff TM, Arumugam TV, Shiels IA, Reid RC, Fairlie DP, Taylor SM. A potent human C5a receptor antagonist protects against disease pathology in a rat model of inflammatory bowel disease. THE JOURNAL OF IMMUNOLOGY 2004; 171:5514-20. [PMID: 14607958 DOI: 10.4049/jimmunol.171.10.5514] [Citation(s) in RCA: 92] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The complement system is implicated in the pathogenesis of human inflammatory bowel disease, but the specific role of C5a has never been examined. We have compared the efficacy of an orally active human C5a receptor antagonist (AcPhe[Orn-Pro-D-cyclohexylalanine-Trp-Arg]), prednisolone, and infliximab against trinitrobenzene sulfonic acid (TNBS)-induced colitis in rats. The drugs were administered either 2 days before or 24 h after TNBS instillation, and rats were then examined after 8 days. Drug-free colitis control rats showed severe disease pathology with significant mortality (39%). Rats pre or posttreated with the C5a antagonist (10 mg/kg/day peroral, 0.3 mg/kg/day s.c.) had reduced mortality and significantly improved macroscopic scores, colon edema, colon myeloperoxidase levels, reduced concentrations of TNF-alpha levels in the colon and serum, and had greater food intake resulting in greater weight gains than colitis-only rats. Rats pretreated with prednisolone (1 mg/kg/day s.c.) displayed significant improvement in parameters measured, but posttreatment was ineffective. Single dose pretreatment with the TNF-alpha inhibitor infliximab (3 mg/kg i.v.) also had significant improvements in the parameters measured. Rats pretreated with a combination of the C5a antagonist and prednisolone showed no greater improvements than either drug alone. These findings suggest a central role for complement, particularly C5a, in the pathology of TNBS-induced colitis in rats, indicating a possible therapeutic role for C5a antagonists in inflammatory bowel disease.
Collapse
Affiliation(s)
- Trent M Woodruff
- Department of Physiology and Pharmacology, School of Biomedical Sciences, University of Queensland, Brisbane, Australia
| | | | | | | | | | | |
Collapse
|