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ARS Home » Plains Area » Houston, Texas » Children's Nutrition Research Center » Research » Publications at this Location » Publication #142704
Title: GROWTH HORMONE DECREASES PROTEIN CATABOLISM IN CHILDREN WITH CYSTIC FIBROSIS

Author
item HARDIN, DANA - UT SOUTHWESTERN MEDICAL
item Ellis, Kenneth
item DYSON, MAYNARD - COOK CHILDREN'S HOSPITAL
item RICE, JULIE - UT SOUTHWESTERN MEDICAL
item MCCONNELL, RUTH - TEXAS CHILDREN'S HOSPITAL
item SEILHEIMER, DAN - TEXAS CHILDREN'S HOSPITAL

Submitted to: Journal of Clinical Endocrinology and Metabolism
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/7/2001
Publication Date: 9/1/2001
Citation: Hardin,D.S., Ellis,K.J., Dyson,M., Rice,J., McConnell,R., Seilheimer,D.K. 2001. Growth hormone decreases protein catabolism in children with cystic fibrosis. Journal of Clinical Endocrinology and Metabolism. 86(9):4424-4428.

Interpretive Summary: Children with cystic fibrosis may not grow at a normal rate and often have low body weight or lean tissue mass, despite aggressive nutritional and dietary efforts. A drug, called growth hormone, can be used to stimulate increased growth rates. However, the exact mechanism of how this drug works remains only partly known. In this study, we examined how one specific protein, called leucine, is used by the body when the children receive growth hormone. A one-year study was conducted, and the 10 children receiving growth hormone were compared with 9 children who were not receiving the drug. The results indicate that growth hormone increases the rate at which complex proteins in the diet are broken down into simpler molecules which improves the body's efficiency resulting in increased amounts of lean tissue.

Technical Abstract: Despite aggressive nutritional therapy, low body weight and protein catabolism are common problems in children with cystic fibrosis. Previous studies by our group and others have demonstrated improvement in both height and weight in children with cystic fibrosis who were treated with human recombinant GH, and our group has recently documented improved clinical status and lean tissue mass as well. The purpose of this report is to summarize our findings of the effect of GH on whole body protein kinetics in cystic fibrosis and to relate these findings to changes in TNF-alpha levels. We conducted a 1-yr study of 19 prepubertal childen with cystic fibrosis (age 7-12 yr, all <94% of ideal body weight). Ten children were randomly assigned to take daily injections of GH (0.3 mg/kg/wk), and nine were randomly assigned to be controls. Baseline results from the subjects with cystic fibrosis were compared with results obtained from nine age- and gender-matched healthy children. Whole body protein turnover was measured at baseline and every 6 months using the stable isotope [1-13C]leucine and mass spectrometric analysis. Leucine rate of appearance, a measure of protein catabolism, was similar in both cystic fibrosis subgroups at baseline and was significantly higher than in the control children without cystic fibrosis. Treatment with GH resulted in a significantly lower leucine rate of appearance, as well as significantly lower leucine oxidation. The rate of protein synthesis, as calculated from these numbers, actually decreased in the cystic fibrosis subgroup. TNF-alpha levels were higher in both cystic fibrosis subgroups than in controls and correlated with leucine rate of appearance. The results of this study suggest that one reason GH improves body weight and lean tissue mass is due to improved whole body protein catabolism and improved efficiency of whole body protein kinetics.