Somatomedin activity and cartilage [35S]sulphate incorporation in the growth-retarded neonatal rat.

Plasma somatomedin activity, cartilage metabolism and the levels of insulin and growth hormone were studied during relative neonatal malnutrition in the rat, produced by the small and large litter method. In growth-retarded rats reduced somatomedin activity and raised growth hormone concentration were found. Neither basal cartilage activity nor cartilage responsiveness to somatomedin was altered in the growth-retarded animals.