Growth of two children after six months interruption of GH therapy

We describe two short boys with normal GH responses to the stimuli in whom GH therapy was interrupted for 6 months. Their growth rates before and after the interruption, and after readministration of GH were evaluated. Height velocity (HV) in case 1 before and after the interruption was 6.6 cm/y and 5.0 cm/y, respectively. HV was not increased (5.0 cm/y) by re-initiation of GH therapy despite the high serum IGF-1 level. Height velocity (HV) in case 2 before and after the interruption was 5.6 cm/y and 3.6 cm/y, respectively. HV was slightly increased to 4.1 cm/y by readministration of GH, but it was far below the pretreatment value. Serum IGF-1 was increased by GH in this case as well. We conclude that re-acceleration of growth by re- administration of GH after interruption of therapy, as seen in classical GHD patients, may not be expected in normal short children.