Expression of Heparin‐Binding EGF‐Like Growth Factor (HB‐EGF) in Bovine Endometrium: Effects of HB‐EGF and Interferon‐τ on Prostaglandin Production

Contents Heparin‐binding EGF ‐like growth factor ( HB ‐ EGF ) regulates several cell functions by binding to its membrane receptor ( E rb B 1 and E rb B 4). Experimental evidences suggest that HB ‐ EGF , prostaglandins ( PG s) and interferon‐τ ( IFN ‐τ) regulate uterine function for pregnancy establishment in ruminants. In this study, the m RNA expressions of HB ‐ EGF , E rb B 1 and E rb B 4 in bovine endometrium and the effects of HB ‐ EGF and IFN ‐τ on PGE 2 and PGF 2‐α production by endometrial cells were investigated. RT ‐ PCR analysis revealed that HB ‐ EGF m RNA was greater at the mid‐luteal stage than at the early and regressed luteal stages (p < 0.05). E rb B 1 m RNA expression was greater at the mid‐ and late luteal stages than at the other luteal stages (p < 0.05). IFN ‐τ increased the expression of HB ‐ EGF , E rb B 1 and E rb B 4 m RNA in epithelial cells (p < 0.05). HB ‐ EGF did not affect PGF 2‐α or PGE 2 production by bovine endometrial epithelial cells, but increased PGF 2‐α and PGE 2 production by bovine endometrial stromal cells (p < 0.05). IFN ‐τ significantly decreased HB ‐ EGF ‐stimulated PGF 2‐α (p < 0.05), but not PGE 2 (p > 0.05) production by stromal cells. These results indicate that HB ‐ EGF and its receptors expression changed in bovine endometrium throughout the oestrous cycle. IFN ‐τ increased their expression in cultured endometrial cells. HB ‐ EGF and IFN ‐τ have the ability to regulate PG s production by stromal cells and therefore may play a role in the local regulation of uterine function at the time of implantation in cattle.