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ARS Home » Plains Area » Houston, Texas » Children's Nutrition Research Center » Research » Publications at this Location » Publication #98218
Title: LEAN BODY MASS DEFICIT IN GIRLS WITH RETT SYNDROME IS NOT ASSOCIATED WITH ALTERED UREA PRODUCTION AND SALVAGE

Author
item Motil, Kathleen
item SCHULTZ, REBECCA - BAYLOR COLL OF MEDICINE
item KERTZ, BARBARA - BAYLOR COLL OF MEDICINE
item BAHAR, ALI - BAYLOR COLL OF MEDICINE
item GLAZE, DANIEL - BAYLOR COLL OF MEDICINE

Submitted to: Pediatric Research
Publication Type: Abstract Only
Publication Acceptance Date: 2/19/1999
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Background: Girls with Rett Syndrome (RS) have persistent deficits in lean body mass (LBM) despite nutritional rehabilitation. Alterations in body protein metabolism may contribute to the deficits in lean body mass in RS. Objective: To determine if increased urea nitrogen (N) production and diminished urea N salvage account for the deficits of protein deposition in RS girls. Methods: We characterized urea N metabolism in the postabsorptive (PA) and fed states in 8 RS girls and 5 healthy controls (C). All subjects were given diets of known protein and energy content for 4 days. Rates of urea N production (UNP) were determined by administering a primed, constant infusion of 15N2-urea for 8 h. Blood samples were obtained during isotopic plateau to determine the 15N enrichments of urea by electron impact gas chromatography-mass spectrometry. Urine samples were collected for 24 h to determine rates of urea N excretion (UNE). The proportion of urea N that was salvaged for N metabolic needs was calculated from the amount of urea N retained (UNP-UNE) and total daily urea N produced in the PA and fed states (TUNP). The amount of food consumed was determined by test-weighing all meals. The protein (P) and energy (E) content of the food was estimated from a nutrient database. The protein-energy ratio (PER) was calculated as the proportion of total E intake derived from protein. Conclusions: UP in the PA, but not fed, state and UNE were lower in RS than in C girls; the proportion of urea that was recycled was not different between groups. TUNP was associated (p<0.05, r=0.83)with dietary PER in C, but not RS, girls. Dietary protein may be a limiting nutrient at this level of intake and contribute to lean body mass deficits in these individuals.