Dietary components responsible for the regulation of somatomedin-C in humans were assessed in five adult volunteers of normal weight who were fasted for 5 d on three occasions, then refed three diets of differing composition. The serum somatomedin-C decreased from a mean prefasting value of 1.85 ± 0.39 U/ml (± 1 SD) to 0.67 ± 0.16 U/ml at the end of fasting (P < 0.005). After refeeding for 5 d with a normal diet, the mean serum somatomedin-C increased to 1.26 ± 0.20 U/ml. A protein-deficient (32% of control), isocaloric diet resulted in a significantly smaller increase, to a mean value of 0.90 ± 0.24 U/ml (P < 0.05). A diet deficient in both protein and energy led to a further fall in mean serum somatomedin-C concentrations to 0.31 ± 0.06 U/ml. The changes in somatomedin-C during fasting and refeeding correlated significantly with mean daily nitrogen balance (r = 0.90). We conclude that both protein and energy intake are regulators of serum somatomedin-C concentrations in adult humans, and energy intake may be of greater importance. The correlation between changes in somatomedin-C and nitrogen balance suggests that the former are directly related to changes in protein synthesis and may be helpful in assessing the response to nutritional therapy.
CITATION STYLE
Isley, W. L., Underwood, L. E., & Clemmons, D. R. (1983). Dietary components that regulate serum somatomedin-C concentrations in humans. Journal of Clinical Investigation, 71(2), 175–182. https://doi.org/10.1172/JCI110757
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