Growth velocity and serum aminoterminal propeptide of type III procollagen in precocious puberty during gonadotropin-releasing hormone analogue treatment.

Growth velocity and serum aminoterminal propeptide of type III procollagen (P-III-NP) were evaluated in 11 girls (age 3.8-8.5 years) with central precocious puberty during luteinizing hormone releasing hormone (LH-RH) analogue treatment (D-Trp6-LH-RH, 60 micrograms/kg im for 28 days, n = 7; D-ser(TBU)6-LH-RH, 1600 micrograms/day intranasally, n = 4). Before treatment, growth velocity (10.2 +/- 1.9 cm/year) and P-III-NP concentrations (12.8 +/- 4.3 micrograms/l) were in the pubertal range. During therapy, growth velocity significantly decreased to the prepubertal levels. P-III-NP concentrations decreased significantly after six months of therapy (7.9 +/- 3.7 micrograms/l, p < 0.001). Three girls with low growth velocity ( < 4 cm/year), stimulated growth hormone peak < 10 micrograms/l, and altered 12-h nocturnal growth hormone secretion at 12 and/or 18 months of treatment, had a more marked decrease in P-III-NP concentrations (patient 3: -65.9%; patient 5: -58.7%; patient 10: -61.0%) after 6 months of therapy. Our results suggest that LH-RH analogue treatment in central precocious puberty may impair growth. In these cases, measurement of serum P-III-NP levels may be an additional marker to monitor growth.