Ultrafiltration in single isolated human glomeruli.
To determine the ultrafiltration properties of human glomeruli, we induced filtration in vitro and estimated the glomerular ultrafiltration coefficient, Kf or LpA, and the glomerular capillary hydraulic conductivity, Lp, in single glomeruli from 17 human kidneys retrieved for allotransplantation. Cadaver donors ranged in age from 2 to 46 years. Filtration was induced in individual isolated glomeruli by abruptly lowering the protein concentration of the medium surrounding a glomerulus to produce a transcapillary oncotic gradient. The events which occurred were recorded on videotape for analysis. Kf was calculated from the maximum rate of glomerular swelling during filtration. Initial glomerular diameter for the individuals studied ranged from 146 +/- 2 microns (age, 2 years) to 292 +/- 6 microns (age, 42 years). Kf ranged from 5.1 +/- 0.8 to 30.7 +/- 3.0 nl/min . mm Hg and varied directly with donor age and glomerular size. The glomerular filtering area was estimated from the formula A = 3 pi D2 and from morphometrically measured basement membrane surface density. Lp was calculated from Lp = Kf/A. Lp using A = 3 pi D2 (LpD) averaged 3.7 +/- 0.2 microliter/min . mm Hg . cm2. To compare the hydraulic conductivity of glomeruli from children and adults, Lp was also calculated using the total basement membrane area derived from measured surface density (LpS).(ABSTRACT TRUNCATED AT 250 WORDS)
D000293:Adolescent; D000328:Adult; D001485:Basement Membrane / Q000502:physiology; D002102:Cadaver; D002196:Capillaries / Q000502:physiology; D002199:Capillary Permeability; D002648:Child; D002675:Child, Preschool; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D066298:In Vitro Techniques; D007678:Kidney Glomerulus / Q000098:blood supply / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D009997:Osmotic Pressure; D010477:Perfusion; D013997:Time Factors; D014462:Ultrafiltration; D014743:Videotape Recording