COMPARATIVE EXPRESSION OF TGF-ALPHA AND EGF GENES IN THE OVINE CONCEPTUS AND UTERINE ENDOMETRIUM IN THE PERIIMPLANTATION PERIOD

Control of growth and differentiation during mammalian embryogenesis m ay be regulated by growth factors. With the use of a very sensitive me thod, the reverse transcription-polymerase chain reaction, expression of some growth factor transcripts was examined during ovine peri-impla ntation development. Transcripts for transforming growth factor-alpha (TGF-alpha) were found in day 15 to day 30 conceptuses, and in uterine tissues. Epidermal growth factor (EGF) was not detectable in any ovin e stages or tissues studied. TGF-alpha could be the normal physiologic al ligand for the epidermal growth factor receptor present on the trop hoblastic tissues, and its expression pattern suggests an autocrine an d paracrine role in the growth and differentiation of ovine embryos.