TY - JOUR
T1 - Short- and Long-Term Effects of Growth Hormone (GH) Replacement on Protein Metabolism in GH-Deficient Adults
AU - Shi, Jianjian
AU - Sekhar, Rajagopal V.
AU - Balasubramanyam, Ashok
AU - Ellis, Kenneth
AU - Reeds, Peter J.
AU - Jahoor, Farook
AU - Sharma, Morali D.
PY - 2003/12
Y1 - 2003/12
N2 - Reduced fat-free mass (FFM) in GH-deficient (GHD) adults is improved by GH replacement, but the protein metabolic changes are unclear. Using iv [ 2H3]leucine and oral 1-[13C1] leucine infusions and dual emission x-ray absorptiometry, we compared leucine kinetics and body composition in eight GHD adults and eight healthy controls in the fasted and fed states, before and after 2 wk and 6 months of GH replacement. Leucine kinetics were not different between pretreatment GHD subjects and controls. After 2 wk of GH treatment, leucine oxidation decreased in the GHD subjects compared with baseline values [fasted, 41 ± 6 vs. 30 ± 5 μmol/kg FFM·h (P < 0.01); fed, 49 ± 3 vs. 41 ± 3.6 μmol/kg FFM·h (P < 0.05)], leucine balance improved [fasted, -14 ± 4 vs. -3.5 ± 3 μmol/kg FFM·h (P < 0.01); fed, 65 ± 10 vs. 72 ± 7 μmol/kg FFM·h (P = 0.07)], and protein synthesis increased [fasted, 116 ± 5 vs. 131 ± 6 μmol/kg FFM·h (P < 0.05); fed, 103 ± 6 vs. 116 ± 6 μmol/kg FFM·h (P < 0.05)]. After 6 months of GH treatment, these changes were not maintained in the fed state. The five GHD subjects with decreased FFM at baseline showed a significant increase after 6 months of GH treatment (P < 0.05). GH replacement in GHD acutely improves protein balance by stimulating synthesis and inhibiting catabolism. After 6 months, protein kinetics reached a new homeostasis to maintain the net gain in FFM.
AB - Reduced fat-free mass (FFM) in GH-deficient (GHD) adults is improved by GH replacement, but the protein metabolic changes are unclear. Using iv [ 2H3]leucine and oral 1-[13C1] leucine infusions and dual emission x-ray absorptiometry, we compared leucine kinetics and body composition in eight GHD adults and eight healthy controls in the fasted and fed states, before and after 2 wk and 6 months of GH replacement. Leucine kinetics were not different between pretreatment GHD subjects and controls. After 2 wk of GH treatment, leucine oxidation decreased in the GHD subjects compared with baseline values [fasted, 41 ± 6 vs. 30 ± 5 μmol/kg FFM·h (P < 0.01); fed, 49 ± 3 vs. 41 ± 3.6 μmol/kg FFM·h (P < 0.05)], leucine balance improved [fasted, -14 ± 4 vs. -3.5 ± 3 μmol/kg FFM·h (P < 0.01); fed, 65 ± 10 vs. 72 ± 7 μmol/kg FFM·h (P = 0.07)], and protein synthesis increased [fasted, 116 ± 5 vs. 131 ± 6 μmol/kg FFM·h (P < 0.05); fed, 103 ± 6 vs. 116 ± 6 μmol/kg FFM·h (P < 0.05)]. After 6 months of GH treatment, these changes were not maintained in the fed state. The five GHD subjects with decreased FFM at baseline showed a significant increase after 6 months of GH treatment (P < 0.05). GH replacement in GHD acutely improves protein balance by stimulating synthesis and inhibiting catabolism. After 6 months, protein kinetics reached a new homeostasis to maintain the net gain in FFM.
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U2 - 10.1210/jc.2002-021943
DO - 10.1210/jc.2002-021943
M3 - Article
C2 - 14671176
AN - SCOPUS:0347362881
VL - 88
SP - 5827
EP - 5833
JO - Journal of Clinical Endocrinology and Metabolism
JF - Journal of Clinical Endocrinology and Metabolism
SN - 0021-972X
IS - 12
ER -