Premium
Concentrations of Na+ and Cl‐ in transplacental ultrafiltrate in sheep.
Author(s) -
Faber J J,
Anderson D F
Publication year - 1995
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1113/jphysiol.1995.sp020868
Subject(s) - transplacental , chemistry , andrology , chromatography , zoology , biology , medicine , pregnancy , fetus , genetics , placenta
1. Maternal blood was made transiently hypertonic by rapid I.V. infusion of a concentrated mannitol solution into pregnant ewes bearing lambs with an indwelling flow sensor and vascular catheters. 2. The transplacental flows of water and of Na+ and Cl‐ were calculated from the umbilical arteriovenous differences in the concentrations of 125I‐labelled albumin and electrolytes, and the fetal placental blood flow. 3. The reflection coefficients of Na+ and Cl‐ were calculated by means of the Patlak equation and found to be 0.85 +/‐ 0.04 and 0.68 +/‐ 0.04 (means +/‐ S.E.M.). The filtration coefficient was 1.02 x 10(‐7) +/‐ 0.12 x 10(‐7) cm5 dyne‐1 s‐1. 4. The results fitted best to an equivalent pore radius in the placental barrier smaller than the currently accepted 0.44 nm but not less than 0.35 nm.