Abstract
The mechanism of growth retardation in many nutritional deficiency states has not been delineated. Somatomedin (SM) is depressed after prolonged fasting or in severe malnutrition despite elevated growth hormone (GH) concentrations, suggesting both nutrition and GH may act as modulators of SM. We have studied the effects of varying concentrations of dietary protein (2.5, 5, 10, 20%) and specific dietary amino acid deficiencies on body and organ weights, GH, SM, cartilage glycosaminoglycans (GAGS) and biochemical composition of brain and liver. Changes in body weights and organ weights were similar for 2.5% protein, a valine deficient or a tryptophane deficient diet (-10%). An increase of 177% was observed for animals on a complete amino acid diet or a 20% protein diet. Arginine deficiency had an intermediate effect. Biochemical alterations were more striking in liver than in brain. Serum SM ranged from 0.20 units for rats on the valine and tryptophane deficient diet to 1.44 units for the rats on the complete diet. SM was positively correlated with the protein content of the diet, body and organ weight changes, food efficiency and cartilage GAGS content and negatively correlated with GH concentrations. These data suggest that dietary protein and amino acids play a direct role in the modulation of SM activity and the growth retardation associated with some nutritional deficiency states may be related to its additional effect on SM activity.
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Reeves, R., Voss, J., Dickinson, L. et al. 461 ROLE OF DIETARY PROTEIN AND AMINO ACIDS IN THE MODULATION OF PLASMA SOMATOMEDIN ACTIVITY IN RATS. Pediatr Res 12 (Suppl 4), 440 (1978). https://doi.org/10.1203/00006450-197804001-00466
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DOI: https://doi.org/10.1203/00006450-197804001-00466