Demonstration of normal plasma somatomedin concentrations in cystic fibrosis

Abstract

WITH THE IMPROVEMENT in longevity in cystic fibrosis, retardation of skeletal growth has become a common manifestation 1, o and has been generally attributed to inability to meet the increased calorie demands of obstructive lung disease, chronic infection, and malabsorption. In protein-calorie malnutrition, which has been proposed as a model for the growth failure of CF, plasma somatomedin levels are usually low, often in the face of elevated levels of growth hormone? 7 It has been suggested that this suppression of SM generation represents the body's effort to shunt caloric and amino acid substrates away from general anabolic uses, so as to satisfy critical energy demands of vital organsY Lee et al have recently reported decreased bioassayable SM activity in six children with CF and have proposed that growth retardation in this disease is caused by a defect in the hypothalamic-pituitary-somatomedin generating system, secondary to protein malnutrition. The significance of these data may be questioned, however, because of