Abstract The outcome of ischemic acute renal failure (IARF) is better in young than adult rats. Insulin-like growth factor I (IGF-I) treatment may increase mortality of adult rats with IARF, probably because of an exagger- ated inflammatory response. We report the response to IGF-I therapy in young rats with IARF. Male rats, aged 28±1 days, with IARF were given subcutaneous IGF-I, 50 μg/100 g at 0, 8, and 16 h after reperfusion (IGF) or were untreated (ARF). Sham-operated rats were used as controls. At 2 and 7 days after ischemia, serum urea ni- trogen and histological damage score, cell proliferation, apoptosis, neutrophil infiltration, and IGF-I receptor mRNA in kidneys were analyzed. The degree of renal failure, mortality rate, histological damage, cell prolifer- ation, and neutrophil infiltration were not different be- tween IGF-I and ARF rats. Hence, short-term IGF-I treatment did not modify the course of IARF in young rats. Keywords Acute renal failure · Ischemia · Rat · Insulin-like growth factor-I · Neutrophil · Inflammation Introduction Acute renal failure (ARF) is defined as a sudden decline of renal function with resultant accumulation of poten- tially toxic metabolic substances. The reduction in glom- erular filtration rate, together with ARF-induced exacer- bation of protein catabolism [1, 2], leads to retention of nitrogenous waste products and, subsequently, to elevat- ed serum levels of creatinine and urea nitrogen (SUN) [3]. Although the incidence of ARF in the pediatric popu- lation is about a fifth of that found in adults [3, 4], it re- mains a significant problem in children. It accounts for 0.2% of pediatric admissions in tertiary referral chil- dren’s hospitals [5], and in neonates and small infants the incidence is comparable to that of adults [6, 7, 8, 9]. The introduction of dialysis in the treatment of ARF in the 1950s reduced overall mortality caused by this syn- drome from 80% to 25% [10]. Since then, the mortality rate has remained substantially invariable [4, 11, 12] in spite of the multiple technological and pharmacological advancements in the treatment of these patients [3, 13]. Although the etiology of ARF is frequently multifac- torial, in newborns and small infants ARF is nearly al- ways secondary to ischemia and hypoxia of kidneys caused by other organ failure [14]. Following the isch- emic injury, renal function and kidney histology undergo progressive deterioration over a period ranging from 48 to 72 hours. If the individual survives, a progressive re- covery process is initiated, resulting in total or partial restitution of the renal function, depending on the severi- ty of the tissue lesion, on associated factors (malnutri- tion, nephrotoxic drugs, hemodynamic situation, etc.), and on the available therapeutic measures [15, 16, 17]. Over the last few years, several lines of investigation have been developed to find a suitable therapeutic agent, which should promote cellular growth and differentia- tion, improve renal hemodynamics, reduce inflamma- tion, and maintain vascular integrity [18]. To this end, diuretics, dopamine, atrial natriuretic factor, calcium channel antagonists, and growth factors have been tested A. Medina · F. Santos ( ✉ ) · B. Amil · J. Rodríguez · M. Crespo Department of Pediatrics, Hospital Central de Asturias, SESPA, Asturias, Spain e-mail: fsantos@correo.uniovi.es Tel.: +34-985103585 A. Medina · M. Fernández-Fuente · F. Santos · B. Amil J. Rodríguez · M. Crespo Department of Pediatrics, School of Medicine, University of Oviedo, Oviedo, Asturias, Spain E. Carbajo-Pérez Department of Anatomy, School of Medicine, University of Oviedo, Oviedo, Asturias, Spain M. Fernández-Fuente · E. Carbajo-Pérez · F. Santos · J. Rodríguez · M. Crespo Instituto Universitario de Oncologia del Principado de Asturias, University of Oviedo, Oviedo, Asturias, Spain F. Santos Pediatría, Facultad de Medicina. C/Julián Clavería s/n, 33006 Oviedo, Asturias, Spain Pediatr Nephrol (2002) 17:1005–1012 DOI 10.1007/s00467-002-0979-y ORIGINAL ARTICLE Alberto Medina · Marta Fernández-Fuente Eduardo Carbajo-Pérez · Fernando Santos Benito Amil · Julián Rodríguez · Manuel Crespo Insulin-like growth factor I administration in young rats with acute renal failure Received: 18 April 2002 / Revised: 26 July 2002 / Accepted: 26 July 2002 / Published online: 14 November 2002 © IPNA 2002