Immunohistochemical localization of transforming growth factor-beta 1 beta 2 during folliculogenesis in the quail ovary

Immunohistochemical methods were used to show the presence and distribution of transforming growth factor-beta 1 and beta 2 during folliculogenesis in quail ovarian tissues. The results indicated that both transforming growth factor-beta subtypes are present. Immunolabelling for transforming growth factor-beta 1 demonstrated that prelampbrush oocytes are immunoreactive in the Balbiani complex, and developing and pre-ovulatory oocytes in the zona radiata. Immunolabelling was also associated with granulosa cells. The number of stained granulosa cells decreased during folliculogenesis. In the pre-ovulatory follicles, immunolabelling was found predominantly in the theca interna. Immunolabelling for transforming growth factor-beta 2 was associated with the zona radiata of developing and pre-ovulatory follicles, and with stromal interstitial cells. Moderate immunoreactivity was found in the Balbiani complex of prelampbrush oocytes. Weak immunolabelling was localized in the granulosa cells of prelampbrush follicles, and in a few cells of the theca interna of pre-ovulatory follicles. The immunolocalization of transforming growth factor-beta 1 and -beta 2 in the quail ovary supports their autocrine and/or paracrine role in avian ovarian processes.