Sulphation factor (somatomedin activity) in experimental protein malnutrition in the rat

In a rat model of protein malnutrition in which the failure of growth is a major feature, a low level of bioassayable sulphation factor activity was present in the serum, associated with normal levels of growth hormone and low insulin in the plasma. The administration of pharmacological doses of human or bovine growth hormone did not increase the amount of sulphation factor activity in the serum or the width of the tibial epiphyses in the protein-malnourished animals. The basal and serum-stimulated incorporation of 35SO2-4 into the costal cartilages of malnourished animals did not differ from that of controls, which suggests that the responsiveness of the end-organs was normal.