AbstractBackgroundFibroblast growth factor receptor 1 (FGFR1) mRNA can be alternatively spliced to generate isoforms containing (FGFR1α) or lacking (FGFR1β) the first immunoglobulin‐like domain. We examined which isoforms are expressed by cultured prostate cells, their affinities for FGF‐2, and the effect of heparin on FGF‐2 binding.MethodsFGFR1 isoform expression was examined by RT‐PCR. FGFR1α and FGFR1β were expressed in CHO cells mutant in heparan sulfate synthesis, and their affinities for FGF‐2, FGF‐1, FGF‐4, and FGF‐6 were determined in the presence and absence of heparin.ResultsFGFR1α was expressed in luminal epithelial cells, whereas FGFR1β was expressed in basal epithelial and smooth muscle cells. FGFR1β bound FGF‐2 with three–fourfold higher affinity than FGFR1α both in the presence and absence of heparin. Heparin increased affinity of both receptor isoforms for FGF‐2 approximately four–fivefold.ConclusionsProstate smooth muscle and basal epithelial cells are likely to be more sensitive than luminal epithelial cells to the low concentrations of FGFs present in vivo. Prostate © 2006 Wiley‐Liss, Inc.