Immunohistochemical localization of inhibin and steroidogenic enzymes in the ovary of common tree shrew (Tupaia glis) and northern smooth-tailed treeshrew (Dendrogale murina)

To study the ovarian function of the Order Scandentia, the localization of inhibin and steroidogenic enzymes (3 beta -hydroxysteroid dehydrogense/isom erase and aromatase) in the ovaries of common tree shrew (Tupaia glis) and northern smooth-tailed tree shrew (Dendrogale murina) was immunohistochemic ally analysed. As in the results reported for other mammals, inhibin alpha -chain was localized in the follicular epithelium of secondary or Graafian follicles in the two species. The localization of aromatase in the ovary of these two species, however. was different. In the common tree shrew, the a romatase was localized in the thecal cells, whilst ill other mammals it is localized in the granulosa cells. These results indicate that in the ovary of the common tree shrew, the of oestradiol may be synthesized in the theca l cells.