Ontogeny of Single Glomerular Perfusion Rate in Fetal and Newborn Lambs

摘要: Summary: The developmental pattern of regional glomerular density and perfusion rate (GPR) was studied in 20 chronically catheterized fetal lambs between 106 140 days gestation (term, 145 days) six newborn 3 19 age. present study demonstrates for the first time that nephrogenic zone disappears around 130 total counts per kidney fetuses over (468296 ± 41173 glomeruli kidney) is not significantly different than (433704 21553). Glomerular density, determined four cortical zones (zone I being outermost portion cortex) did show any significant changes during life; however, decreases were observed each after birth. relative distribution life decreased outer (zones II) increased inner III IV) cortex as matured approached term. After birth, this difference became even more prominent; fraction I) from 49.6 2.9% less 120 to 37.8 1.5% (P gestation. During same period, filtration (FF) increase whereas a 16.12 1.66% lambs. Renal vascular resistance 1.03 0.08 mm Hgml-1 min-1 >130 0.51 0.05 Hgml-1min-1 206.9 16.8 161.3 20.7 nl/min lambs, respectively), doubled (from 55.6 10 119.5 8.9 lambs) remained unchanged IV when compared GPR values. GFR correlated closely with (r = 0.87) II 0.87), suggesting birth may depend on renal cortex. Speculation: addition new nephron units be an important determinant (GFR) In gestation, no longer factor explain but other factors such increases surface area filtration, effective pressure capillar coefficient then play role. one can speculate decrease major postnatal GFR.