Concentrations of Na+ and Cl‐ in transplacental ultrafiltrate in sheep.

J. J. Faber, D. F. Anderson

Research output: Contribution to journalArticlepeer-review


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.

Original languageEnglish (US)
Pages (from-to)159-167
Number of pages9
JournalThe Journal of Physiology
Issue number1
StatePublished - Aug 15 1995
Externally publishedYes

ASJC Scopus subject areas

  • Physiology


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