Administration of recombinant human growth hormone stimulates protein synthesis, decreases urea generation, and improves nitrogen balance in individuals with normal renal function. However, little information is available concerning the effects of growth hormone in patients with renal disease. This pilot study evaluated urea kinetics and clinical/metabolic responses to short-term growth hormone administration in five clinically stable adult patients requiring maintenance hemodialysis for end-stage renal failure. The dialysis prescription, medications, and oral calorie and protein intake of each patient remained constant during an initial control week and a subsequent 2-wk growth hormone treatment period. During treatment, growth hormone (5 or 10 mg) was administered s.c. immediately after each dialysis session. Protein and calorie intake, vital signs, body weight, and other clinical parameters remained stable throughout the 3-wk study. BUN values fell significantly (approximately 20 to 25%) during growth hormone administration compared with control week values. Similarly, urea kinetic modeling demonstrated a significant reduction in urea generation and the protein catabolic rate during each week of growth hormone treatment. Plasma insulin-like growth factor I levels rose significantly, and serum phosphorus and intact parathyroid hormone levels fell significantly during growth hormone administration. Serum glucose and other blood values remained stable. This preliminary study suggests that growth hormone administration reduces urea generation and improves the efficiency of dietary protein utilization in stable adult hemodialysis patients. Growth hormone may be a useful adjunctive therapy to diminish body protein catabolism in this patient population.