Growth hormone promotes somatic and skeletal muscle growth recovery in rats following chronic protein-energy malnutrition.
The efficacy of recombinant human growth hormone (GH) and/or a diet enriched in protein and energy to improve growth recovery following prolonged malnutrition was examined in male rats food-restricted from birth until 120 d of age. At d 121, restricted rats were randomly assigned to recovery groups receiving either a control or enriched diet with or without daily subcutaneous injections of GH. Rats were killed after 16 or 47 d of recovery. At d 16, GH treatment stimulated liver, heart, plantaris, soleus, carcass and body weight gain and inhibited fat gain when compared to recovery controls. Rats receiving GH also exhibited the highest serum insulin-like growth factor-I (IGF-I) concentrations and total muscle protein. At d 47, GH effects on body and muscle recovery were minimal, and differences among recovery groups in serum IGF-I concentration and total muscle protein were no longer present. Consumption of an enriched diet increased fat pad and liver mass, but did not promote muscle recovery. There were no differences among treatment groups in skeletal muscle IGF-I mRNA levels at d 16 or 47. In summary, GH had positive effects on somatic and skeletal muscle growth early in the recovery process, possibly via endocrine IGF-I-stimulated protein accretion. In contrast, the enriched diet promoted fat deposition with no impact on skeletal muscle growth recovery.
Gautsch
T A
TA
Division of Nutritional Sciences and the Department of Food Science and Human Nutrition, University of Illinois, Urbana, IL 61801, USA.
Kandl
S M
SM
Donovan
S M
SM
Layman
D K
DK
D000273:Adipose Tissue / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism; D000704:Analysis of Variance; D000818:Animals; D002908:Chronic Disease; D004247:DNA / Q000096:biosynthesis; D004044:Dietary Proteins / Q000008:administration & dosage / Q000627:therapeutic use*; D002149:Energy Intake; D005508:Food Deprivation; D019382:Human Growth Hormone / Q000627:therapeutic use*; D007328:Insulin / Q000097:blood; D007334:Insulin-Like Growth Factor I / Q000378:metabolism / Q000502:physiology*; D008099:Liver / Q000378:metabolism; D008297:Male; D024510:Muscle Development; D018482:Muscle, Skeletal / Q000254:growth & development*; D009929:Organ Size / Q000187:drug effects; D011502:Protein-Energy Malnutrition / Q000188:drug therapy*; D051381:Rats; D017207:Rats, Sprague-Dawley
D004044:Dietary Proteins; D007328:Insulin; D019382:Human Growth Hormone; D007334:Insulin-Like Growth Factor I; D004247:DNA