Erythropoietin production by the fetal liver in an adult environment
AW Flake, MR Harrison, NS Adzick and ED Zanjani
To gain insight into the mammalian liver to kidney erythropoietin (Ep)
switch, we heterotopically transplanted livers from preswitch, switched,
and postswitch fetal and newborn lambs into normal adult sheep. Recipients'
serum Ep and circulating reticulocyte levels were serially determined until
rejection of the graft and compared with identical samples from
sham-operated control adult ewes. Transplantation of preswitch and switched
fetal livers caused an impressive rise in recipients' serum Ep activity and
provoked a corresponding increase in reticulocytosis. In contrast, Ep
activity and reticulocyte counts did not change from preoperative levels in
adult ewes transplanted with postswitch livers or in the sham-operated
controls. The production of Ep by the preswitch fetal liver in the adult
environment was not dependent on the presence or absence of host kidneys
and was stimulated by anemic hypoxia. These results suggest that the fetal
liver is capable of producing relatively large amounts of Ep activity, and
the production of Ep can be maintained in the adult environment in the
presence of functional adult kidneys. This argues against suppression of
liver Ep production by renal Ep, or some other factor in the postnatal
environment, and suggests that the liver to kidney switch of Ep production
during ontogeny may represent a genetically determined event.
Volume 70,
Issue 2,
pp. 542-545,
08/01/1987
Copyright © 1987 by The American Society of Hematology
