Uric acid clearance in newborns and infants

Abstract

The present investigation deals with some aspects of the renal physiology of the newborn and the infant, in comparison with the normal renal function of the adult and was particularly directed towards the rate and the nature of the renal excretion of uric acid. Despite the metabolic importance of this substance and the large number of studies dealing with it, there is still no agreement even on the problem of evaluating the total daily uric acid excretion of the newborn and of the infant. Most of the studies were conducted on newborns. In these subjects earlier authors (7, 8, 9) reported a relatively high uric acid excretion, but, more recently, Barlow and McCance (1) found a low output: such discrepancies can probably be attributed to the lack of specificity of the older methods. Moreover, no clearance studies are available giving exact data as to how uric acid is handled by the kidney of newborns and infants. That is surprising, considering that uric acid is a very interesting substance from the point of view of kidney physiology. A number of studies have established the fact that uric acid is actively reabsorbed by the tubular cells (11) ; the possibility of tubular excretion of this substance is, however, still very doubtful. A further purpose of our study was to elucidate the pathogenesis of the so-called uric acid infarcts, which can easily be found at post-mortem examination of the kidneys of newborns.