RENAL FUNCTION IN EARLY LIFE

Abstract

Author''s conclusions: "In this review a short description has been given of the anatomy, cellular chemistry and physiology of the infant''s kidney. It has been shown to differ in all these respects from the adult organ, but it is not yet possible to correlate these differences to any extent or to discuss the functional immaturity of the newborn organ in terms of development, anatomy and cellular metabolism. In the future no doubt it will be possible to do this. If it is permissible to generalize about the functional differences, it may be said that the kidneys of animals begin to form and to secrete a fluid which resembles urine before birth. They continue to do so after birth and there is probably no great functional development at that time. In the early days or weeks of life the newborn kidney is, however, a less effective organ than it will later become. Thus the glomerular filtration rates are lower and the clearances of all those substances which are excreted mainly by glomerular filtration are necessarily also lower. The tubules have not yet acquired, to the full, their capacity to excrete creatinine, diodone or p-aminohippuric acid, but their ability to reabsorb sodium, chloride and phosphate ions may develop more quickly than the glomerular filtration rate so that a very high proportion of these ions may be reabsorbed from the glomerular filtrates. Functionally, moreover, the kidney of the newborn animal has little flexibility. It excretes water, sodium chloride and urea, but if the mutual relationships of these in the internal environment are disturbed, the kidney makes a relatively feeble attempt to restore the status quo and this is true even when the disturbance has been very great. There is some slight evidence also that the same may be true of pH. In the light of these results a study of the capacity and limitations of the kidney in the early days of life seems to be an important subject for research. If all is normal, the kidney of a baby will do the work required of it[long dash]Nature has seen to that[long dash]but if the child has become dehydrated, acidosed, or otherwise abnormal, or has to undergo some surgical operation, then the duty of the pediatrician must be to assist the kidney to restore and maintain the normality of the internal environment and he requires for this purpose all the knowledge with which the investigator can supply him.".