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Insulin‐like growth factor‐I raises serum procollagen levels in children and adults with Laron syndrome
Author(s) -
Klinger B.,
Jensen L. T.,
Silbergeld A.,
Laron Z.
Publication year - 1996
Publication title -
clinical endocrinology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.055
H-Index - 147
eISSN - 1365-2265
pISSN - 0300-0664
DOI - 10.1046/j.1365-2265.1996.7990809.x
Subject(s) - medicine , n terminal telopeptide , endocrinology , procollagen peptidase , pyridinoline , insulin like growth factor , short stature , bone remodeling , protein precursor , type i collagen , growth factor , biology , alkaline phosphatase , enzyme , biochemistry , receptor , osteocalcin
OBJECTIVE Recombinant IGF‐I is now available for the treatment of GH insensitivity (Laron syndrome). We have determined the effects of IGF‐I on soft connective tissue and bone metabolism in a group of patients with this disorder.PATIENTS AND DESIGN Thirteen patients with Laron syndrome (LS) (8 children and 5 adults) were included in the study. The children with LS were treated with IGF‐I for 3 years with daily doses of 150–200 μg/kg. The adult LS patients were treated for 9 months with daily doses of 50–120 μg/kg. Blood samples for procollagens were collected before, during and at the end of IGF‐I treatment.MEASUREMENTS Serum levels of the carboxyterminal propeptide of type I procollagen (PICP), the aminoterminal propeptide of type III procollagen (PIIINP) and of the pyridinoline cross‐linked carboxyterminal telopeptide of type I collagen (ICTP) were determined before and during IGF‐I administration.RESULTS Untreated patients with LS had lower than normal serum levels of PICP and PIIINP for age. IGF‐I treatment increased significantly the PIIINP levels in children from 7.2 ± 2.8 (SD) to 12.5 ± 2.2 μg/l ( P < 0.001), and in adults from 2.7 ± 1.0 to 8.4 ± 3.6 μg/l ( P < 0.001); serum PICP increased from 243 ± 123 to 384 ± 190 μg/l ( P < 0.087) in children, and in adults from 43.4 ± 8.1 to 135.8 ± 41.9 μg/l ( P < 0.001). ICTP levels in children increased from 9.7 ± 3.7 to 14.3 ± 5.9 μg/l ( P < 0.001) and in adult patients levels increased from 3.6 ± 0.9 to 5.5 ± 2.2 μg/l ( P < 0.001) during treatment and returned to basal values after stopping IGF‐I administration.CONCLUSIONS Low procollagen levels in untreated Laron syndrome patients and their rise during replacement therapy with IGF‐I provide evidence that IGF‐I plays an important role in bone and soft connective tissue metabolism and that serum procollagen may serve as a marker to reflect some of the biochemical changes induced by IGF‐I in connective tissue in the initial periods of treatment.