Imitation of normal plasma growth hormone profile by subcutaneous administration of human growth hormone to growth hormone deficient children

Abstract

The time course of human plasma growth hormone (hGH) levels following s.c. and i.m. injection of hGH was studied in 12 children with GH deficiency who had received long-term treatment with i.m. injections of highly purified hCH. Also the spontaneous diurnal GH levels in 8 normal children of comparable age were recorded. Blood samples were obtained during 24 h after i.m. and s.c. injections of 4 IU/m2 hGh and analyzed for immunoreactive hGH. While a median peak value of 160 ng/ml (range 135-475 ng/ml) was obtained 2 h after i.m. injection, s.c. injection resulted in a more sustained elevation reaching 41 ng/ml (range 32-51 ng/ml) at 6 h subsiding slowly with a median concentration of 15 ng/ml (range 5-24 ng/ml) persisting after 14 h. Gel chromatography demonstrated that the hGH immunoreactivity of blood samples obtained as late as 14 h after s.c. injection had unaltered molecular size. Seven of the patients were further studied after s.c. injection of 2 IU/m2 at 2000 h instead of in the morning. A plasma profile was attained during the night which roughly approximated the average nocturnal plasma pattern of the normal children.