OBJECTIVE: Erythropoietin receptors (EPO-R) were recently detected in nonerythroid cells, e.g. in fetal spinal cord, brainstem and brain. Since 1987, when Pedonen and coworkers reported on erythropoietin binding sites in different fetal tissues, we know that the lungs may also express a receptor for erythropoietin. To our knowledge this hypothesis has never been proven by molecular genetic methods. To test the hypothesis we studied fetal pulmonary tissue.

METHODS: We studied 19 fetal tissue samples from fetuses born between 18 and 32 weeks of gestational age. The pregnancy termination was carried out because of severe fetal malformations or chromosomal aberrations. The specimens were taken from the lungs during a routine post mortem examination. Tissues were immediately frozen in liquid nitrogen. After the preparation of total RNA a reverse transcription of RNA was done, followed by cDNA amplification. The m-RNA for the extra- and intracellular domains of the EPO-R were detected by PCR.

RESULTS: In 16 out of 19 specimens of fetal pulmonary tissue EPO-R m-RNA could be detected. Negative probes were tested three times.

CONCLUSION: The EPO-R is expressed in fetal pulmonary tissue. There is great evidence that the erythropoietin binding sites detected by Pekonen et al. are identical with the EPO-R. Our study gives no indication for the possible function of the EPO-R.