Serum somatomedin activity assayed by the enhancement of proteoglycan sulphation using chick embryo chondrocytes in normal children at various ages and childen of short stature

Abstract

It was possible to obtain a sufficient amount of homogeneous chondrocytes from 13-day old chick embryo-sterna in an 8-day suspension culture. Serum somatomedin (SM) activity was measured on the basis of the ability of serum to stimulate labelled sulphate uptake in these chondrocytes. Somatomedin A and multiplication stimulating activity (MSA) stimulated the sulphation in this assay. Serum SM activity in term cord sera and newborn sera was lower than that in normal adults.Serum SM activity in early infants increased rapidly and attained the levels of that in normal adults within 1 month following birth. Serum SM activity in infants (1 month \p=m-\2 years) and pubertal children(10\p=n-\16 years), when the annual height increment is greatest, was higher than that in normal adults.Serum SM activity in children with constitutinal dwarfism aged 6\p=n-\10 years and over 10 years was normal and lower, respectively, compared to that in age-matched controls.

Stimulation of glycosaminoglycan synthesis by somatomedin and insulin in rat chondrocytes via somatomedin receptors.

“…There are many factors which regulate skeletal growth. It is well known that somatomedin is one of the growth factors that stimulate glycosaminoglycan (GAG) synthesis, and DNA synthesis in cartilage in vitro (Zingg and Froesch 1973, Ash and Francis 1975, Froesch et al, 1976, Ashton and Francis 1977, Maesaka et al, 1982 and skeletal growth in vivo (van Buul-Offers et al, 1979, Schoenle et al, 1982. Receptors for somatomedins have been demonstrated in placenta, liver, fibroblast, cartilage, etc.…”