[The influence of IGF-1 on the biosynthesis of type I and III colagen during puberty]

The influence of insulin-like growth factor I (IGF-I) on the biosynthesis of type I and III collagen during puberty was studied.

Eighty-four healthy girls aged from 9.8 to 14.7 years were included into this study. After careful physical examination all girls were divided into three groups according to pubertal development. To assess pubertal stage we performed breast examination according to Tanner (bd). Group I consisted of 26 girls in prepubertal stage (1 of bd); group II (stage 2 and 3 of bd) 29 girls, and group III (stage 4 and 5 of bd)--27 girls. Serum concentration of PICP (C-terminal propeptide of type I collagen), PIIINP (N-terminal propeptide of type III collagen, as well as IGF-I were assessed by RIA methods.

The highest mean values of serum PICP and PIIINP were found in girls in the second group (stage 2 and 3 of bd) whereas the lowest values were observed in group III (stage 4 and 5 of bd). The mean serum concentration of IGF-I presented a steady increase as puberty advanced being highest in girls in group III. No correlation was found between IGF-I and PICP and IGF-I and PIIINP. A positive correlation were observed between mean serum concentration of IGF-I and age (R = 0.52; p < 0.0001), height (R = 0.51; p < 0.0001), and body weight (R = 0.47; p < 0.0001) in investigated groups.

Although IGF-I showed a steady increase during puberty no correlation was observed between its serum concentration and markers of collagen biosynthesis (PICP and PIIINP).