Ontogeny of erythropoietin gene expression in the sheep fetus: Effect of dexamethasone at 60 days of gestation

Abstract

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 < .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.