ABSORPTION KINETICS AND METABOLIC EFFECTS OF GH FOLLOWING SUBCUTANEOUS INJECTIONS IN THE ABDOMEN VERSUS THE THIGH

Abstract

The significance of changing the site of injection on the absorption and metabolic effects of human growth hormone (GH) was studied. In a cross-over design nine GH-deficient patients were randomized to subcutaneous (s.c.) injections of GH in the thigh or abdomen. After each treatment period (four weeks), serum profiles of GH, IGF-I, IGFBP-3, glucose, insulin and glucagon were measured for 37 hours after GH injection (3 IU/m2) (19.00 h). Mean (± SEM) integrated levels (AUC) of GH (μg/l) were similar: 2.63 ± 0.38 (thigh) versus 2.67 ± 0.31 (abdomen)(NS). AUC (μg/l) for the initial six hours were significantly different: 1.11 ± 0.23 (thigh) and 1.50 ± 0.27 (abdomen)(p< 0.05). Cmax (μg/l) [11.59 ± 1.93 (thigh) and 14.83 ± 2.39 (abdomen) (p = 0.19)] was achieved faster following s.c. injection in the abdomen. Tmax (hours) was 5.89 ± 0.41 (thigh) and 4.26 ± 0.49 (abdomen) (p< 0.002). IGF-I levels were similar. AUC's (± SEM) were 345.6 ± 62.0 (thigh) and 355.7 ± 65.1 (abdomen)(NS). Levels of IGFBP-3 were however different [AUC's (± SEM) (μg/l) were 2044.3 ± 147.7 (thigh) and 2287.9 ± 181.5 (abdomen)(p=0.05)]. Insulin, glucose and glucagon levels were not significantly different. We conclude that subcutaneously injected human GH is absorbed faster when injected in the abdomen as compared with the thigh. Metabolic effects of GH were similar. Levels of IGFBP-3 however were higher after s.c. injectiops in the abdomen.