Document Type

Thesis - University Access Only

Award Date

2005

Degree Name

Master of Science (MS)

Department / School

Health, Physical Education, and Recreation

Abstract

Purpose: This study was designed to investigate the impact of negative and positive energy balance (using commonly prescribed weight loss and weight gain caloric alterations) on serum concentrations of!GF-1 and relative amounts of serum JGFBP-3 during S days of physical activity. Accordingly, the central hypothesis of this study is that the main effect of positive energy balance will result in greater serum concentrations of JGF-1 and favorable changes in blood and urine markers of whole body protein breakdown, while negative energy balance will result in decreased serum concentrations of IGF-1 and unfavorable changes in whole body protein breakdown. Methods: Eleven males (23.6 ± 0.7 years) were assigned to one of three trials in a random, cross-over, design. Each trial was of varying caloric intake (NEG: -S00, BAL: balanced; POS: +S00 kcals/d) but with equal proportions of carbohydrates (SO%), proteins (30%) and fat (20%). In addition, each subject ran daily on a treadmill at 65-70%, of VO2max for approximately 30 minutes, the time needed to expend S00 kcals. Blood samples were obtained each morning for the measurement of serum concentrations of IGF-1 and relative amounts of serum JGFBP-3 and 24h urine collection was obtained prior to beginning the treatment protocol and again on the final day of exercise to determine urinary creatinine and urea nitrogen concentrations (day S). The main effect of caloric intake was analyzed using a repeated measures analysis of variance with time and treatment as factors (JMPin v .4.0.4 ). A Tukey post-hoc test was used to locate differences. The level of significance was set at p<0.05.

Results: There was no time by treatment effect for IGF-I, IGFBP-3, urinary nitrogen or urinary creatinine despite significant differences in energy balance and body weight during each trial. Conclusion:

The data from this study indicates that an energy deficit or surplus of 500 kcals when combined with daily aerobic exercise is not enough of a stimulus to impact serum IGF-I or IGFBP-3 levels in healthy, college-aged males.

Key Words: INSULIN-LIKE GROWTH FACTOR-I, INSULIN-LIKE GROWTH FACTOR BINDING PROTEIN-3, EXERCISE, ENERGY BALANCE, DIET.

Library of Congress Subject Headings

Insulin-like growth factor-binding proteins

Somatomedin

Energy metabolism

Exercise for men -- Physiological aspects

Format

application/pdf

Number of Pages

77

Publisher

South Dakota State University

Download

Share

COinS