Endocrine Abstracts

Aim: Procollagen type III N-terminal peptide (P3NP) occurs during type III collagen synthesis. Previous studies about the GH misuse in athletes proved the P3NP as a growth hormone (GH) responsive biomarker. We evaluate the P3NP levels and correlate with IGF1 depending on GH status.

Subjects and Methods: We determined P3NP levels in 81 prepubertal children (35 girls) with a mean age of 6.2 y.o [3.37–9.95]. The group consists of 37 subjects with normal height, 18 subjects with growth hormone deficiency (GHD) and 26 subjects with non-GHD short stature. We measured P3NP with a commercially available (for research purpose) ELISA kit (catalog code: DL-PIIINP-Hu) with the detection range 62.5–4000 pg/ml.

Results: In 50 subjects with values of IGF1 below 0 SDS, we found a negative correlation of P3NP and IGF1 (rs=−0.292, P=0.039). Even not statistically significant, P3NP correlate negatively with height-SDS (rs=−0.210, P=0.144). 26 values of P3NP were out of the reference range for this biomarker. Five of these records belongs to GHD subjects with conditions that can explain high P3NP levels (hypothyroidism in the context of multiple pituitary deficiencies, trauma or inflammation). We analyzed 55 registrations with P3NP in the normal range available for the whole group, according to GH status. We found higher P3NP levels, expressed as median of SD in the GHD group compared to normal stature children (M=0.7, n=9 vs M=−0.17, n=28) and this difference was statistically significant U=70.5, z=1.96, P=0.049).

Conclusion: The lack of GH-IGF1 effect in GHD children could lead to normal -high levels of P3NP because this biomarker of collagen synthesis is not effectively incorporated into collagen supportive tissues.