Ontogeny of erythropoietin gene expression in the sheep fetus: effect of
dexamethasone at 60 days of gestation
GB Lim, K Jeyaseelan and EM Wintour
Howard Florey Institute of Experimental Physiology and Medicine, University
of Melbourne, Parkville, Victoria, Australia.
We have used competitive reverse transcription and polymerase chain
reaction (RT/PCR) to compare the levels of erythropoietin (Epo) mRNA in the
liver and kidneys of the sheep fetus at 60, 80, 100, 130, and 140 days of
gestation (term = 145 to 150 days). The effect of dexamethasone infusion in
the ewe on Epo gene expression in the 60-day fetus was also investigated.
Epo mRNA levels were highest at 60 days of gestation, the earliest age
studied, in both liver and kidney. In the liver, Epo mRNA expression
declined as gestation proceeded. Kidney Epo mRNA was maintained at a high
level until 100 days of gestation, declining significantly in the 130-day
fetus (P < .01). Treatment of ewes carrying 60-day fetuses with 0.76
mg/h dexamethasone for 48 hours resulted in a significant decrease in fetal
plasma Epo values and Epo mRNA levels in both the liver and kidney. In the
dexamethasone-treated fetuses, Epo mRNA in the liver was 52% of control
values (P < .05), and in the kidney, 33% of control (P < .001). The
results suggest that the kidney may play a more important role as a site of
Epo synthesis in the early gestation sheep fetus than previously thought.
Glucocorticoids may have a role in the regulation of Epo gene expression.
Volume 84,
Issue 2,
pp. 460-466,
07/15/1994
Copyright © 1994 by The American Society of Hematology
