Altered glomerular permselectivity to neutral dextrans and
heteroporous membrane modelling in human pregnancy.
Roberts, Mark, Marshall D. Lindheimer, and John M. Davison.
Departments of Obstetrics and Gynaecology, University of Newcastle
upon Tyne, Newcastle Upon Tyne, NE1 4LP, UK. and Medicine, Obstetrics
and Gynecology, and Clinical Pharmacology, University of Chicago,
Chicago, IL 60637, US
APStracts 2:0149F, 1995.
Hyperfiltration precedes renal function loss in several nephropathies.
Animal studies suggest this may be due to accompanying increases in
transglomerular capillary hydrostatic pressure difference (_P) and/or
altered glomerular processing of macromolecules. Renal hemodynamics
increase strikingly in human pregnancy. To test the hypothesis that
these alterations are not potentially harmful, clearances of inulin,
p-aminohippurate and neutral dextrans were measured at 16 and 36wk
gestation then 4mth post-partum in 11 normotensive women. Results
were analysed using 2 computer modelling programs. Glomerular
filtration rate (GFR) and renal plasma flow (RPF) were markedly
elevated in early and late pregnancy (135+/-6 & 895+/-53 and
135+/-6 & 754+/-32, ml/min, respectively, vs. 87+/-7 & 520+/
-17, ml/min, post-partum). Gestational hyperfiltration was primarily
due to RPF increments with a minor contribution from decrements in
capillary oncotic pressure. Fractional dextran clearances,
(particularly the smaller dextrans, 30-39[angstrom]a radii), were
lower in early pregnancy, decreasing further in late pregnancy. There
was no evidence of increased _P and alterations in glomerular
membrane porosity resolved post-partum. These data provide a database
to study effects of pregnancy on chronic renal disease.
Received 30 May 1995; accepted in final form 21 August 1995.
APS Manuscript Number F172-5.
Article publication pending Am. J. Physiol. (Renal Fluid Electrolyte
Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 15 September 1995.