Paediatric renal allograft recipients frequently manifest growth retardation because of suboptimal graft function and/or concomitant corticosteroid treatment. To determine if the growth-suppressive effects of methylprednisolone (MP) could be counterbalanced by concomitant treatment with recombinant human growth hormone (rhGH) under conditions of normal and reduced renal function, the following animal model was set up. Female uraemic Sprague-Dawley rats (140 g) together with pair-fed and ad libitum-fed control animals were treated with 6 mg/kg per day MP with or without 10 IU/kg per day rhGH. MP suppressed linear growth and weight gain by 43% and 63%, respectively in ad libitum-fed normal control animals; the suppression was more pronounced in uraemic animals (57% and 107%, respectively). The suppressive effects were independent of food intake. The food conversion ratio (weight gain/food intake) was diminished to one-third in control and to more than one-tenth in uraemic animals. Concomitant treatment with rhGH completely reversed the suppression of length gain and weight gain (total body and muscle) and normalized the food conversion ratio. We concluded that rhGH can completely reverse the catabolic effects of corticosteroids under conditions of normal or reduced renal function. The data provide a reasonable rationale for prospective controlled studies on the use of rhGH treatment in paediatric kidney transplant recipients with growth failure.