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Blood—cerebrospinal fluid transfer of plasma proteins during fetal development in the sheep
Author(s) -
Dziegielewska K. M.,
Evans C. A. N.,
Malinowska D. H.,
Møllgård K.,
Reynolds M. L.,
Saunders N. R.
Publication year - 1980
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.1980.sp013172
Subject(s) - blood proteins , choroid plexus , transferrin , fetus , albumin , cerebrospinal fluid , endocrinology , medicine , serum albumin , biology , blood plasma , chemistry , pregnancy , central nervous system , genetics
1. The penetration of human and sheep plasma proteins from blood into c.s.f. of sheep fetuses (57‐86 days gestation) has been studied. The proteins were injected intravenously via cotyledonary vessels. After different time periods the c.s.f. concentrations of marker proteins were estimated by radioactive counting of iodinated human or sheep proteins or by immunoassay of human proteins. 2. Several proteins of similar molecular size penetrated into c.s.f. to a different extent in 60 day fetuses. The steady‐state c.s.f.: plasma ratios were about 15% for human AFP, 10% for human transferrin and sheep albumin, 7% for human α 1 ‐antitrypsin, and 5% for human albumin. In older fetuses the penetration of protein from blood into c.s.f. was much reduced and no evidence for differential penetration of different proteins was found. 3. The penetration of human AFP, transferrin and sheep albumin from blood into c.s.f. was greater than can be accounted for by passive diffusion. 4. The results of this paper are discussed in relation to those of the preceding paper on the identification and quantification of proteins in fetal c.s.f. and plasma. The hypothesis is put forward that the choroid plexus of the immature (60 days and less) sheep fetus contains a mechanism for the transcellular transfer of plasma proteins which may be selective in nature and of importance for some aspects of brain development.