EXPRESSION OF TRANSFORMING GROWTH-FACTOR-BETA MESSENGER-RNA IN CHICKEN OVARIAN FOLLICULAR TISSUE

RNA was isolated from chicken thecal tissue from the largest (F1), thi rd largest (F3), and fifth largest (F5) preovulatory follicles, from s mall yolky follicles, and from granulosa tissue from F1 follicles. Tra nsforming growth factor-beta (TGF-beta) gene expression was measured u sing reverse transcription polymerase chain reaction. Thecal cells fro m all follicle sizes expressed all three isoforms of TGF-beta. TGF-bet a(1) mRNA was detected in granulosa cells at levels comparable to thos e seen in thecal cells. However, TGF-beta(2) and TGF-beta(3) mRNA was expressed at significantly lower levels in granulosa than in thecal ti ssue. This is the first demonstration of TGF-beta gene expression in t he ovary of a nonmammalian species. The similarities between mammalian and avian TGF-beta gene expression are remarkable, especially in ligh t of the distinctive patterns of avian follicular development and the differing steroidogenic capacities of ovarian cell types of the two cl asses of vertebrates. (C) 1995 Academic Press, Inc.