Somatomedin A in male puberty. Variation with age, maturity, growth and androgens.

Bioassayable somatomedin-A (SM-A) and serum concentrations of testosterone (T) and dehydroepiandrosterone (DHEA) were determined longitudinally in 26 normal boys during puberty. The mean trend of SM-A increased in relation to age, pubic hair development and peak height velocity (PHV) and significant correlations were observed with testicular volume, height velocity and T (all P less than 0.001) but not with DHEA. In relation to growth SM-A increased mainly during 12 to 6 months prior to PHV but no further increase was seen in the 6 months thereafter. Thus pubertal growth and development have to be taken into account in the evaluation of changes in bioassayable SM-A concentrations in boys.