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Zn‐binding globulin in human fetal brain and liver: a marker for passive blood/CSF transfer of protein
Author(s) -
Dziegielewska K. M.,
Bell J. E.,
Matthews N.,
Møllgård K.,
Saunders N. R.
Publication year - 1993
Publication title -
neuropathology and applied neurobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.538
H-Index - 95
eISSN - 1365-2990
pISSN - 0305-1846
DOI - 10.1111/j.1365-2990.1993.tb00408.x
Subject(s) - fetus , cerebrospinal fluid , biology , staining , endocrinology , pathology , cerebrum , central nervous system , gestation , amniotic fluid , medicine , pregnancy , genetics , neuroscience
The presence of Zn‐binding globulin (ZnbG) during human fetal development was studied in cerebrospinal fluid (CSF) and plasma with immunodiffusion methods and in brain, CSF, plasma and liver using immunocytochemical methods. At the earliest stages examined with immuno‐cytochemistry (5–6 weeks gestation) no staining for ZnbG was visible in liver, plasma, CSF or brain. However, the primitive mesenchyme exhibited a prominent staining reaction. In late embryonic and early fetal stages, staining for the protein was most prominent in the spinal cord, brain stem and diencephalon and in the choroid plexuses and marginal and subplate zones in the telencephalon. At the cellular level, synaptic strata and territories were most strongly stained. The distribution of ZnbG in the early developing central nervous system suggests that this protein may be involved in the initial establishment of CNS circuitry. Embryonic brain was positive for ZnbG well before the protein could be detected in CSF, plasma or liver. The early occurrence of ZnbG in brain tissue prior to its presence in liver or plasma also suggests that the protein is synthesized in early fetal brain. At the time when CSF first became positive (17 weeks gestation), the brain staining had largely disappeared. ZnbG in plasma increased throughout gestation to reach 2.6 ± 0.4 mg/100 ml at term and subsequently increased to an adult value of 6.8 ± 1.5 mg/100 ml. The CSF to plasma ratio did not change significantly during development and was low (1–2%) at all fetal ages examined when compared with other plasma proteins; this is consistent with passive transfer between the two compartments both in the fetus and in the adult.