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

The time course of plasma growth hormone (hGH) levels following sc and im injection of hGH was studied in 12 children with growth hormone deficiency who had received long-term treatment with im injections of highly purified hGH. Also the spontaneous diurnal GH levels in 8 normal children of comparable age were recorded. Blood samples were obtained during 24 h after im and sc injections of 4 IU/m2 hGH and analysed for immunoreactive hGH. While a median peak value of 160 ng/ml (range 135 to 475 ng/ml) was obtained 2 h after im injection, sc injection resulted in a more sustained elevation reaching 41 ng/ml (range 32 to 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 sc injection had unaltered molecular size. Seven of the patients were further studied after sc injection of 2 IU/m2 at 20.00 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.