DISTRIBUTION PATTERN OF F-ACTIN, VIMENTIN AND ALPHA-TUBULIN IN THE BOVINE TESTIS DURING POSTNATAL-DEVELOPMENT

The distribution of F-actin, vimentin and alpha-tubulin was studied im munohistochemically in bovine seminiferous and straight testicular tub ules, rete testis and intertubular tissue during postnatal development . Sites of antigenicity were detected by ABC immunoperoxidase techniqu e and visualized by metal-enhanced deposition of diaminobenzidine. Wit hin the seminiferous epithelium, F-actin appears at 20 weeks and is fo und in adult Sertoli cells as part of specialized cell contacts, In pe ritubular cells, F-actin increases gradually from 4 to 30 weeks when t he adult concentration is achieved. After 20 weeks, subepithelial fibr oblasts of the mediastinum testis start to express F-actin and at 52 w eeks, a thick layer of positive myofibroblasts is seen beneath the epi thelia of rete testis and straight testicular tubules. Testicular macr ophages and light intercalated cells (LIC) are also characteristically decorated following F-actin immunoreaction. Vimentin is localized in perinuclear position in pre-Sertoli cells of 4-20 weeks and in adult S ertoli cells. During the period of transformation from pre-Sertoli to Sertoli cells, the perinuclear vimentin coat is absent. The epithelia of rete testis and straight tubules exhibit a strong vimentin immunore action in their basal parts, This specific pattern does not change fro m 4 weeks to adulthood, alpha-Tubulin is absent in 4-week-old seminife rous tubules, At 8 weeks, the perinuclear area of pre-Sertoli cells re acts positive. The alpha-tubulin content increases in these cells cont inuously, and from 30 weeks on nearly the entire supranuclear cytoplas m of Sertoli cells is heavily decorated. The epithelial of rete and st raight tubules display a growing number of alpha-tubulin-positive cell s from 4 to 40 weeks, From then on, nearly all epithelial cells contai n or-tubulin, particularly in a narrow zone beneath their lateral cell borders.