DISTRIBUTION OF THE INTERMEDIATE FILAMENT PROTEINS VIMENTIN, KERATIN,AND DESMIN IN THE BOVINE OVARY

The distribution of the intermediate filament (IF) proteins desmin, ke ratin, and vimentin was studied immunohistochemically in bovine ovarie s. Special attention was paid to granulosa cells to examine possible m arked changes of IF distribution in relation to folliculogenesis durin g ovarian development. Therefore, ovaries were used from fetuses from 3 months of gestation onward, calves, heifers, and cows. In all ovarie s, desmin immunoreactivity was restricted to smooth muscle cells in bl ood vessel walls. Keratin appeared a characteristic of the ovarian sur face epithelium. Go-localization of keratin and vimentin was observed in the epithelium of rete ovarii tubules in fetuses and calves, and in cortical cord epithelium and pregranulosa cells of primordial follicl es in fetuses at 3-7 months of gestation. Vimentin was demonstrated in endothelium and in fibroblasts. In addition, vimentin immunoreactivit y was present in granulosa cells of primary, secondary, and antral fol licles. In antral follicles, these granulosa cells mainly had an elong ated appearance and either contained an oblong or a round nucleus. Tho se with an oblong nucleus were characteristic for atretic antral folli cles. In nonatretic follicles, numerous vimentin immunoreactive, elong ated granulosa cells with a round nucleus were observed, especially in the peripheral granulosa layer and in small (<3 mm in diameter) antra l follicles. Additionally, in antral follicles, protrusions of vimenti n-positive corona radiata cells were observed, that penetrated the zon a pellucida to contact the oocyte. The data show that the distribution of vimentin containing IFs is associated with various aspects of gran ulosa cell activity, as mitosis, atresia, and intercellular transport. (C) 1995 Wiley-Liss, Inc.