Radioimmunoassay of the carboxyterminal propeptide of human type I procollagen

Abstract

Type I collagen is the most abundant collagen type in soft tissues and the only type found in mineralized bone. We established a rapid equilibrium radioimmunoassay for the carboxyterminal propeptide of human type I procollagen (PICP), to be used as an indicator of the synthesis of type I collagen. We isolated type I procollagen from the medium of primary cultures of human skin fibroblasts, digested the protein with highly purified bacterial collagenase, and purified PICP by lectin-affinity chromatography, gel filtration, and ion-exchange separation on HPLC. The purity of the protein was verified by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and by N-terminal amino acid sequencing of its component chains. The final radioimmunoassay was established with polyclonal rabbit antibodies. Material antigenically related to PICP is readily detected in human serum. There is only one form of the serum antigen, its molecular size and affinity to the antibodies being similar to those of the isolated propeptide. Intra- and interassay CVs are 3% and 5%, respectively. Preliminary reference intervals for healthy adults (18 to 61 years of age) are 38-202 micrograms/L for men and 50-170 micrograms/L for women: in men the concentration is inversely related to age. The serum antigen is stable during storage and after repeated thawing.

Serum markers of bone metabolism in multiple myeloma: prognostic value of the carboxy‐terminal telopeptide of type I collagen (ICTP)

“…9 g/l. The PICP assay measures the C-terminal propeptide of type I procollagen, a trimeric globular protein with a molecular weight of 100 000 units (Melkko et al, 1990). We obtained a normal range for PICP of 50-210 g/l.…”

Endocrine regulation of bone turnover in men

“…The carboxy (C-) terminal propeptides (PICP) and the amino (N-) terminal propeptides (PINP) are measured by specific immunoassays. 18,19 Recent studies suggest that the PINP has greater diagnostic validity than PICP. 20 In particular, anabolic agents such as PTH seem to greatly affect PINP serum levels.…”

Antithyroid therapy improves bony manifestations and bone metabolic markers in patients with Graves' thyrotoxicosis

“…Samples were collected after an overnight fast and stored at ¹80ЊC. Urinary dPYR was measured by an ELISA kit (Metra Biosystems, Mountain View CA, USA) (Delmas et al, 1993), serum ICTP by a radioimmunoassay (RIA) kit (Orion Diagnostica, Turku, Finland) (Risteli et al, 1993), serum OC by an immunoradiometric assay kit (Mitsubishi-Yuka, Tokyo, Japan) (Kawaguchi et al, 1990), PICP by an RIA kit (Orion Diagnostica) (Melkko et al, 1990) and ALP by an automatic clinical analyser (Model 736, Hitachi, Katsuta, Japan). Urinary dPYR concentration was expressed as nmol per mmol urinary creatinine measured by the automatic clinical analyser.…”