Pharmacokinetics and pharmacodynamics of recombinant human growth hormone by subcutaneous jet- or needle-injection in patients with growth hormone deficiency.

Eighteen growth hormone (GH) deficient children and adolescents (11 6/12-20 9/12 y) participated in a randomized open, two-period (4 weeks) cross-over study to evaluate the pharmacokinetics and pharmacodynamics of recombinant human growth hormone (rhGH) administered daily, either by subcutaneous jet-injection or conventional needle-injection. Plasma growth hormone (GH), insulin-like growth factor 1 (IGF-1), insulin-like growth factor binding protein 3 (IGFBP-3), glucose, insulin, HbAlc and serum-free fatty acids (FFA) levels were analysed repeatedly. GH absorption characteristics, expressed as AUC(0-infinity), Cmax and Tmax ratio (%) jet-injected over needle-injected were similar in both groups. IGF-I and IGFBP-3 plasma levels were identical in both groups. Serum FFA concentrations were comparable after GH administration with either injection device. Surprisingly nocturnal blood glucose decreased to asymptomatic hypoglycaemic levels in all patients. The results of this study showed equal responses concerning absorption and bioavailability of growth hormone administered daily for 4 weeks by either a jet- or a needle-injection device in GH-deficient children and adolescents.