All issues > Volume 35(11); 1992

Original Article

J Korean Pediatr Soc. 1992;35(11):1493-1500. Published online November 15, 1992.

Plasma Somatomedin C Levels in Normal Children

Bo Young BY Yun¹, Hoan Jong HJ Lee¹

¹Department of Pediatrics, Seoul National University College of Medicine, Seoul, Korea

Abstract

Somatomedin C, the insulin-like growth factor I is suggested to mediate the growth-promoting effect of growth hormone. Sm-C, mostly bound to plasma protein forming an IGF-I protein complex, is slowly cleared from plasma and thus its plasma concentration is quite constant. A single sampling of blood for Sm-C is sufficient for the measurement of its concentration. For the evaluation of growth hormone deficient and non-deficient dwarfs, measurements of plasma Sm-C may be a useful adjunct to assessment of growth hormone secretion. To determine the Sm-C reference ranges of the age-and sex-matched norms in Korea, plasma levels of Sm-C/IGF-I were measured by specific radioimmunossay in 186 children and adolescents between the ages of 7 and 20 years. All subjects were in good health and between the 3rd and 97th percentiles for height by a standard growth chart. Pubertal stages were determind by the method of Tanncr. The results were as follows; 1) The mean levels of plasma Sm-C gradually increased over the consecutive age groups and reached maximum at the age group of 13~15 years in both males and females. 2) The mean levels of plasma Sm-C in females were significantly higher than those in 7/*- males t all age groups except over 16 years of age. 3) the mean levels of plasma Sm-C reached maximum at 13 years in females and 14 years in males. 4) According to Tanner stage, the mean levels of plasma Sm-C reached maximum at Tanner stage 4 in both males and females. 5) The mean levels of plasma Sm-C in females were higher than those in males at all Tanner stage. In conclusion, the plasma Sm-C levels in normal children in our study can be used as a reference value for the diagnosis of growth hormone deficiency and the response ' fter gr

Keywords :Somatomedin C , Insulin-like growth factor I