Growth velocity, growth hormone therapy, and serum concentrations of the amino-terminal propeptide of type III procollagen.

The relationship between serum concentrations of the amino-terminal propeptide of type III procollagen (PIIINP) and growth was assessed in 307 healthy subjects and 82 children with disorders of growth (41 with insufficient growth hormone, 23 with short stature and normal endocrinologic studies, 18 with tall stature) by means of a recently developed, simplified PIIINP radioimmunoassay. The PIIINP value appeared to be related to height velocity; in healthy children of each sex, the pattern of change with age mirrored the shape of the standard height velocity curve; in children with disorders of growth, there was a statistical correlation (p less than 0.001) between PIIINP concentration and height velocity. However, measurement of serum PIIINP alone had no diagnostic value because there was considerable overlap of PIIINP values in children with growth hormone insufficiency, short stature, normal stature, and tall stature. The most appropriate application of PIIINP may be in the monitoring of prepubertal children receiving exogenous growth hormone therapy; in these patients, increases in height velocity were reflected by increases in PIIINP, and early increases in PIIINP may have predictive value.