Excreción Urinaria de Calicreína en Recién Nacidos

Abstract

Kallikrein excretion and some parameters of renal function were studied on 20, one day old, newborn infants (12 preterm and 8 term infants). Preterm infants excreted less kallikrein (p <0.05), had lower creatinine clearance (p^O.02) and urinary osmolality (p<C0.03) and they showed also higher values of urinary volume (p<0.01), Fe Na + (p<0.01), Fe K (p <0.05), and free water clearace (p<0.02) than infants born at term. Kallikrein excretion related directly with gestational age (p <0.01) and body weight (p <0.03) and inversely with Fe^a + (p < C0.04) and urinary volume (p -CO.Ql). When urinary kallikrein excretion was corrected to body surface these relations lost statistical significance, except with gestational age (p <C0.04). The values of kallikrein excretion in newborns were very low as compared to those of a young adult population. As kallikrein is synthesized in the distal nephron,we have advanced as an hypothesis that this could be a reflection of inmature distal tutbular mass and/or be caused by relative unresponsiveness of the distal nephron of newborn infants to hormones known to stimulate kallikrein in adults, such as aldosterone and antidiuretic hormone. En los mecanismos de regulation de la funcion renal se reconoce la participation de al menos tres sistemas hormonales vasoactivos, tales como el sistema renina-angiotensina-aldosterona, las prostaglandinas renales y el sistema calicrema-