DIFFERENTIAL GENE-EXPRESSION OF FIBROBLAST GROWTH-FACTOR RECEPTOR ISOFORMS IN RAT OVARY

The gene expression of four fibroblast growth factor receptors (flg, b ek, FGFR-3, and FGFR-4) in rat ovary cells was studied. Northern blot hybridization revealed that flg and bek mRNAs were detectable during a ll stages except a diestrus stage, whereas FGFR-3 and FGFR-4 mRNAs wer e almost undetectable throughout the cycles. In situ hybridization als o demonstrated that only flg and bek gene expression was detectable. A modest flg mRNA signal was detected in developing antral follicles an d it was more prominent in the theca-interstitial cells than in the gr anulosa cells. A modest to weak flg mRNA signal was seen in the hypert rophied theca-interstitial cells of atretic follicles and a very weak flg mRNA signal was observed in the corpora lutea. On the other hand, a weak bek mRNA signal was seen in granulosa and theca-interstitial ce lls in developing follicles and also hypertrophied theca-interstitial cells of atretic follicles, but not in the corpora lutea. Intense sign als for both flg and bek mRNAs were unexpectedly found in the epitheli um of paroophoron at the hilus. These results demonstrate that the bFG F receptor isoforms are expressed differentially in the rat ovary cell s.