Change in response with age of human articular cartilage to plasma somatomedin activity

Abstract

Normal male articular cartilage (34 specimens, age range 1–30 years) has been examined in vitro for response to somatomedin (SM) activity. Basal³H-thymidine and³⁵S-sulfate incorporation both decreased with increasing age of the cartilage donor. However, enhancement of isotope incorporation which was attained on addition of 10% normal plasma (containing IU SM/ml) was greatest in cartilage from adolescents in the age range 12–17 years. The mean enhancement of³H-thymidine incorporation (expressed as % basal) was as follows: age 1–10 years=184 ± 28 (SE),N=9; 12–17 years=436 ± 101 (11); 18–30 years=231 ± 49 (8); and for³⁵S-sulfate incorporation was 1–10 years=389 ± 100 (8); 12–17 years=824 ± 273 (11); and 18–30 years=572 ± 56 (8). The increased response of cartilage in the 12–17 year group suggests that a greater sensitivity to the somatomedins may contribute to the increased skeletal growth during adolescence.