Expression of messenger ribonucleic acids encoding for basic fibroblast growth factor (FGF) and alternatively spliced FGF receptor in human fetal ovary and uterus.

Basic fibroblast growth factor (bFGF) is an angiogenic and mitogenic peptide that may have modulatory effects in the adult ovary and uterus. The FGF receptor is a tyrosine kinase and has similar affinity for both acidic FGF and bFGF. The ligand-binding portion of the receptor has three immunoglobulin-like domains. bFGF and the FGF receptor have been localized in the fetal rat ovary and Mullerian duct. bFGF is a proliferative agent recently shown to be vital for long term cultures of mouse fetal primordial germ cells. Expression of bFGF and FGF receptor mRNA have not heretofore been reported in human fetal ovary and uterus. We prepared RNA from whole human fetal ovaries and uteri at 10, 15, 19, and 22 weeks gestation. After reverse transcription of the RNA into cDNA, we used polymerase chain reaction (PCR) primers directed to specific portions of bFGF and the FGF receptor and performed PCR amplification using the fetal cDNA. We found mRNA expression of bFGF and two forms of FGF receptor in all fetal ovaries and uteri at these developmental stages. One of the PCR products for the FGF receptor was the sequence that contained three immunoglobulin-like domains, whereas a second PCR-amplified fragment was consistent with a FGF receptor mRNA that has a 267-basepair deletion in the first immunoglobulin-like loop. We conclude that bFGF and two forms of the FGF receptor mRNA are expressed in human fetal ovary and uterus. The finding that both bFGF and the FGF receptor are concurrently expressed suggests that bFGF may serve as an autocrine or paracrine modulator during early development of the human reproductive tract.