EXPRESSION OF THE GENES ENCODING BASIC FIBROBLAST GROWTH-FACTOR AND ITS RECEPTOR IN HUMAN GRANULOSA-CELLS

The role of basic fibroblast growth factor (bFGF) in granulosa cell on togeny has been previously demonstrated. In this study we evaluated th e possible intraovarian origin of bFGF. Human granulosa cells were mai ntained in primary culture and their cytoplasmic extract was purified by affinity chromatography on a heparin-sepharose column. The column w as then eluted with 10 mM Tris-HCI containing increasing concentration s of NaCl. The chromatographic fractions were tested in a bioassay usi ng bovine adrenal capillary endothelial cells (ACE) as targets. A peak of mitogenic activity was detected in the fraction eluted with the hi ghest salt concentration. This chromatographic profile is similar to t hat of bFGF. The in situ synthesis of this bFGF-like protein was then demonstrated by reverse transcription-polymerase chain reaction. Using oligonucleotide primers specific for the bFGF gene, a single major ba nd of DNA, corresponding to the expected size, was amplified. The iden tity of this fragment with the bFGF corresponding sequence was further demonstrated by restriction enzyme analysis. Moreover, RT-PCR was als o employed to amplify a DNA band specific for the bFGF receptor gene. These data indicate that human granulosa cells are able to synthesize both bFGF and its receptor and, thus, bFGF might participate to the au tocrine mechanisms regulating their growth and differentiated function s.