The absorption profile and availability of a physiological subcutaneously administered dose of recombinant human growth hormone (GH) in adults with GH deficiency.

AIMS

To investigate the absorption profile and estimate the bioavailability of three doses of recombinant human growth hormone (rhGH) smaller than 2 IU in females with GH deficiency (GHD). A second aim of the study was to compare the mean 24 h GH concentrations after s.c. injection of rhGH with the physiological mean 24 h GH concentration of healthy females of comparable age, height, and BMI.

METHODS

Fourteen female patients with substituted GHD, and 14 healthy females of comparable age, height, and BMI were studied. All GHD patients underwent 24 h GH sampling after s.c. injection of rhGH in doses of 0.6, 1.2, or 1.8 IU. In addition, these patients underwent a 4 h GH sampling after i.v. injection of rhGH (1 IU). In healthy subjects, blood was withdrawn every 10 min for 24 h to determine the physiological GH profile.

RESULTS

A s.c. dose of 0.6 IU resulted in a mean and maximum GH concentration of 0.95+/-0.04 mU l(-1) and 2.62+/-0.09 mU l(-1). A doubling (or tripling) of the rhGH dose resulted in a doubling (or tripling) of the mean and maximum GH concentration. The time of maximum GH concentration was reached on average after 261+/-27 min. Mean GH concentration in healthy females was comparable with the mean GH concentration after a s.c. dose of 1.2 IU. Mean availability of the s.c. injected dose was 63%+/-4%.

CONCLUSIONS

A dose of 1.2 IU resulted in a mean GH concentration comparable with the mean physiological GH concentration in healthy females of comparable age, height, and BMI.